The Kynix Blog

IntroductionIn 2025, while surface mount technology (SMT) dominates mass production, the ability to read resistor color codes remains a fundamental skill for electronics prototyping, repairs, and education. Color bands are used to identify leaded resistors, typically with a power rating of up to one watt. The international standard IEC 60062 specifies this coding system, which applies to both resistors and capacitors.This system allows engineers and hobbyists to quickly identify resistance values without a multimeter. While digital marking codes are common on SMD resistors, the color band system remains the global standard for through-hole components.Figure: A guide to the resistor color code standard. Several bands provide the complete data for the component. They indicate the resistance value, tolerance, and sometimes the failure rate (reliability). Resistors typically have between three and six bands. The first two (or three) bands represent the significant digits of the resistance value, followed by a multiplier band. Resistance levels are standardized into specific series (E-series) of preferred values.Video: Visual guide to understanding resistor color codes.Ⅰ 1 Ohm Resistor Color Code1.1 Color Code Of 1 Ohm 4-Band ResistorThe resistor color code table is used to determine the value. Below is the breakdown for a 1 Ohm, 4-band resistor:Figure: Color code of 1Ω 4-band resistor.BandColorValue1st BandBrown 12nd BandBlack 03rd Band (Multiplier)Gold x 0.14th Band (Tolerance)Gold ±5%Calculation1st digit: 12nd digit: 0Multiplier: 0.11 OhmTolerance: ±5% Calculation logic:1st-band = Brown = 1 (1st digit)2nd-band = Black = 0 (2nd digit)3rd-band = Gold = 0.1 (Multiplier)4th-band = Gold = ±5% (Tolerance) Formula: $10 \times 0.1 = 1 \Omega$.Tolerance range: 5% of 1Ω is 0.05Ω. Theoretically, the actual resistance of a 1Ω resistor lies between 0.95Ω and 1.05Ω. Note on Low Values: For low-value resistors (under 10 Ohms), the multiplier band is often Gold (x0.1) or Silver (x0.01). In modern IEC 60062 standards, a Pink band is sometimes used for x0.001 multipliers in high-precision shunts. In 4- and 5-band resistors, the last band indicates tolerance. Gold indicates ±5%, Silver ±10%, Brown ±1%, and Red ±2%. If the fourth band is missing, the tolerance is standardized at ±20% (rare in 2025). 1.2 Color Code Of 1 Ohm 5-Band ResistorThe 1 Ohm 5-band resistor color code is Brown, Black, Black, Silver, Black:Figure: Color code of 1Ω 5-band resistor.1st-band = Brown = 1 (1st Digit)2nd-band = Black = 0 (2nd Digit)3rd-band = Black = 0 (3rd Digit)4th-band = Silver = x 0.01 (Multiplier)5th-band = Black = ±1% (Tolerance) For a 1 Ohm 5-band precision resistor, the calculation is $100 \times 0.01 = 1 \Omega$. The tighter tolerance (Black band = 1%) makes these ideal for current sensing applications. 1.3 Frequently Asked Questions about 1 Ohm Resistor1. What does a 1 ohm resistor do?A 1 Ohm resistor is often used as a current sense resistor (shunt) to measure current flow or to simulate a specific load. In power supplies, it can also act to simulate the ESR (Equivalent Series Resistance) of a large capacitor. 2. What is the definition of 1 ohm?The Ohm is the SI unit of electrical resistance. 1 Ohm is defined as the resistance between two points of a conductor when a constant potential difference of 1 volt applied between these points produces a current of 1 ampere. 3. Is 1 ohm a lot of resistance?No, 1 Ω is a very small amount of resistance. It is close to a short circuit. Resistances in electronic circuits usually range from hundreds (Ohms) to millions (Megaohms). 4. What is the formula for resistance?Rearranging Ohm's Law ($V = I \times R$) gives $R = V / I$. Therefore, 1 Ohm = 1 Volt per Ampere. Ⅱ 10 Ohm Resistor Color Code2.1 Color Code of 10 Ohm 4-Band ResistorThe 4-band 10 Ohm resistor color code is shown below:Figure: Color code of 10Ω 4-band resistor. BandColorValue1st BandBrown 12nd BandBlack 03rd Band (Multiplier)Black x 1 ($10^0$)4th Band (Tolerance)Gold ±5% Calculation:1st band = Brown = 12nd band = Black = 03rd band = Black = Multiplier $10^0$ = 1Result: $10 \times 1 = 10 \Omega$.With ±5% tolerance (0.5Ω), the actual value lies between 9.5Ω and 10.5Ω. Pro Tip: Be careful not to confuse Brown (1st band) and Red bands under poor lighting, as a "Red-Black-Black" sequence would read 20 Ohms. 2.2 Frequently Asked Questions about 10 Ohm Resistor1. What is the power consumed by a 10 ohm resistor with no current?If no current flows (open circuit), the power consumed is zero. 2. What is the current through a 10 ohm resistor in a circuit?Current depends on voltage. For example, if a 10 Ohm resistor is connected to a 6V source with some internal resistance (total circuit resistance 10.8Ω), the current is $I = V/R = 6 / 10.8 \approx 0.55$ Amps. 3. What is the voltage across the 10 ohm resistor?Ohm's Law states $V = I \times R$. If 1.2 Amps flows through a 10 Ohm resistor, the voltage drop is $1.2 \times 10 = 12$ Volts. 4. How much power is dissipated by a 10 ohm resistor?Power is calculated as $P = I^2R$ or $P = V^2/R$.Example: If 12 Volts is applied directly across a 10 Ohm resistor, the current is 1.2A. The power is $P = 1.2^2 \times 10 = 14.4$ Watts. Warning: A standard 1/4 Watt resistor would burn instantly in this scenario. You would need a high-power ceramic resistor. 5. What is a 10 ohm resistor used for?Low-value resistors like 10 Ohms are often used as current limiters in power circuits, in voltage dividers, or as part of RC filters (snubbers) to suppress voltage spikes. Ⅲ 100 Ohm Resistor Color Code3.1 Color Code of 100 Ohm 4-Band ResistorFor a 100 Ohm resistor, the bands are Brown, Black, Brown, Gold.Figure: Color code of 100Ω 4-band resistor. BandColorValue1st BandBrown12nd BandBlack03rd Band (Multiplier)Brownx 10 ($10^1$)4th Band (Tolerance)Gold±5% Calculation:1st digit (Brown) = 12nd digit (Black) = 0Multiplier (Brown) = 10Result: $10 \times 10 = 100 \Omega$.With ±5% tolerance, the resistance ranges from 95Ω to 105Ω. 3.2 Color Code of 100 Ohm 5-Band ResistorA 5-band 100 Ohm resistor allows for higher precision. The sequence is Brown, Black, Black, Black, Gold (or Brown/Red for tolerance).Figure: Color code of 100Ω 5-band resistor.1st-band = Brown = 12nd-band = Black = 03rd-band = Black = 04th-band (Multiplier) = Black = x 1 ($10^0$)5th-band (Tolerance) = Gold (±5%)Calculation: $100 \times 1 = 100 \Omega$. 3.3 Frequently Asked Questions about 100 Ohm Resistor1. What is a 100 ohm resistor used for?It is commonly used for LED protection, gate drive resistance in MOSFET circuits, and signal termination. It fits perfectly into breadboards for prototyping. 2. How can you tell if a resistor is 100 ohm?Look for the color bands: Brown-Black-Brown (4-band) or Brown-Black-Black-Black (5-band). 3. What is the value of 100 ohm in Megaohms?100 Ohms is $0.0001 M\Omega$ ($100 \times 10^{-6}$). 4. What is the actual range of a 100 ohm resistor?With standard ±5% tolerance, it measures between 95Ω and 105Ω. An older ±20% resistor (rare today) would measure between 80Ω and 120Ω. Ⅳ 120 Ohm Resistor Color Code4.1 Color Code of 120 Ohm 4-Band ResistorThe 120 Ohm resistor is famously used in CAN Bus termination. The color code is Brown, Red, Brown, Gold.Figure: Color code of 120Ω 4-band resistor. BandColorValue1st BandBrown12nd BandRed23rd Band (Multiplier)Brownx 104th Band (Tolerance)Gold±5% Calculation:Digits: 1, 2Multiplier: x 10Result: $12 \times 10 = 120 \Omega$.Tolerance range (±5%): 114Ω to 126Ω. 4.2 Frequently Asked Questions about 120 Ohm Resistor1. Why is 120 Ohm the standard for CAN Bus?The characteristic impedance of twisted pair cables used in automotive CAN networks is approximately 120 Ohms. Placing a 120Ω resistor at each end of the bus prevents signal reflections (ringing), ensuring data integrity. 2. Where do you place the 120 Ohm resistor?It is placed between CAN High (pin 7) and CAN Low (pin 2) at the two physical ends of the bus network. 3. Can I measure 120 Ohms on a live CAN bus?If the system is powered down, measuring resistance between CAN High and CAN Low should yield 60 Ohms. This is because there are two 120Ω terminating resistors in parallel ($120 / 2 = 60$). Ⅴ 150 Ohm Resistor Color Code5.1 Color Code of 150 Ohm 4-Band ResistorThe sequence for 150 Ohms is Brown, Green, Brown, Gold.Figure: Color code of 150Ω 4-band resistor. BandColorValue1st BandBrown12nd BandGreen53rd Band (Multiplier)Brownx 104th Band (Tolerance)Gold±5% Calculation:Digits: 1, 5Multiplier: x 10Result: $15 \times 10 = 150 \Omega$.Tolerance range: 142.5Ω to 157.5Ω. 5.2 Frequently Asked Questions about 150 Ohm Resistor1. How do I identify a 150 ohm resistor?Look for the Green band in the second position (representing 5) and the Brown band in the third position (representing x10 multiplier). Ⅵ 220 Ohm Resistor Color Code6.1 220 Ohm Resistor Color Code (5% Tolerance)This is extremely common for driving LEDs from 5V logic.Figure: 220 ohm resistor color code (Red-Red-Brown-Gold). BandColorValue1st BandRed22nd BandRed23rd Band (Multiplier)Brownx 104th Band (Tolerance)Gold±5% Calculation:Digits: 2, 2Multiplier: x 10Result: $22 \times 10 = 220 \Omega$. 6.2 220 Ohm Resistor Color Code (10% Tolerance)If the last band is Silver, the tolerance is ±10%. This means the resistor could be anywhere between 198Ω and 242Ω. 6.3 Frequently Asked Questions about 220 Ohm Resistor1. What does a 220 ohm resistor do?It resists current flow. In 2025, it is the standard "go-to" resistor for limiting current to standard LEDs when powered by USB (5V) or microcontrollers like Arduino or ESP32. 2. Will a 5 volt LED with a 220 ohm resistor run safely?Yes. If a red LED drops 2.0V, the resistor drops the remaining 3.0V. Using Ohm's Law ($I = V/R$), $3.0V / 220\Omega \approx 13.6 mA$, which is a safe and bright current for most indicator LEDs. Power dissipation is minimal ($0.04W$), so a 1/8W or 1/4W resistor is perfect. Ⅶ 330 Ohm Resistor Color Code7.1 Color Code of 330 Ohm 4-Band ResistorSequence: Orange, Orange, Brown, Gold.Figure: Color code of 330Ω 4-band resistor. BandColorValue1st BandOrange32nd BandOrange33rd Band (Multiplier)Brownx 104th Band (Tolerance)Gold±5% Calculation:Digits: 3, 3Multiplier: x 10Result: $33 \times 10 = 330 \Omega$. 7.2 Frequently Asked Questions about 330 Ohm Resistor1. Why use a 330 ohm resistor for an LED?If you need slightly less brightness or are using a 3.3V power supply (common in modern electronics like Raspberry Pi), a 330Ω resistor offers a good balance of brightness and protection. 2. What is the real value of a 330 ohm resistor?With 5% tolerance, it falls between 313.5Ω and 346.5Ω. Ⅷ 470 Ohm Resistor Color Code8.1 Color Code of 470 Ohm 4-Band ResistorSequence: Yellow, Violet, Brown, Gold.Figure: Color code of 470Ω 4-band resistor. BandColorValue1st BandYellow42nd BandViolet73rd Band (Multiplier)Brownx 104th Band (Tolerance)Gold±5% Calculation:Digits: 4, 7Multiplier: x 10Result: $47 \times 10 = 470 \Omega$. 8.2 Frequently Asked Questions about 470 Ohm Resistor1. What is a 470 ohm resistor used for?It is often used to drive blue or white LEDs (which have higher forward voltages) from higher voltage sources like 9V batteries or 12V automotive systems. 2. How do I know if I have a 470 ohm resistor?Look for the distinct Yellow (4) and Violet (7) starting bands. Ⅸ 500 (510) Ohm Resistor Color Code9.1 Color Code of 510 Ohm 4-Band ResistorNote: 500 Ohms is not a standard "E24 series" value. The closest standard value is 510 Ohms. In 99% of circuits, a 510Ω resistor is a perfect substitute for a 500Ω requirement.Figure: Color code of 510Ω 4-band resistor (Green-Brown-Brown-Gold). BandColorValue1st BandGreen52nd BandBrown13rd Band (Multiplier)Brownx 104th Band (Tolerance)Gold±5% Calculation:Digits: 5, 1Multiplier: x 10Result: $51 \times 10 = 510 \Omega$. 9.2 Frequently Asked Questions about 510 Ohm Resistor1. Can you substitute 500 ohm for 510 ohm?Yes. The error is only 2%. Given that standard resistors have a 5% tolerance, 510 Ohms is well within the acceptable range for a "500 Ohm" design. Alternatively, you can place two 1kΩ resistors in parallel to get exactly 500Ω. Ⅹ 1k Ohm Resistor Color Code10.1 Color Code of 1k Ohm 4-Band ResistorThe 1kΩ (1000 Ohm) resistor is arguably the most common resistor in electronics, used extensively for pull-up and pull-down logic circuits.Figure: Color code of 1kΩ 4-band resistor (Brown-Black-Red-Gold). BandColorValue1st BandBrown12nd BandBlack03rd Band (Multiplier)Redx 100 ($10^2$)4th Band (Tolerance)Gold±5% Calculation:Digits: 1, 0Multiplier: Red = x 100Result: $10 \times 100 = 1000 \Omega = 1 k\Omega$. 10.2 Frequently Asked Questions about 1k Ohm Resistor1. What is a 1k ohm resistor used for?It is the industry standard for pull-up resistors on microcontroller pins (like Arduino inputs) to prevent floating signals. 2. What is 1k ohm?"k" stands for Kilo (1000). Thus, 1k Ohm is 1000 Ohms. Ⅺ 2k Ohm Resistor Color Code11.1 Color Code of 2k Ohm 4-Band ResistorSequence: Red, Black, Red, Gold.Figure: Color code of 2kΩ 4-band resistor. BandColorValue1st BandRed22nd BandBlack03rd Band (Multiplier)Redx 1004th Band (Tolerance)Gold±5% Calculation:Digits: 2, 0Multiplier: Red = x 100Result: $20 \times 100 = 2000 \Omega = 2 k\Omega$. Ⅻ 2.2k Ohm Resistor Color Code12.1 Color Code of 2.2k Ohm 4-Band ResistorFamous for the "Three Reds" pattern.Figure: Color code of 2.2kΩ 4-band resistor (Red-Red-Red-Gold). BandColorValue1st BandRed22nd BandRed23rd Band (Multiplier)Redx 100 ($10^2$)4th Band (Tolerance)Gold±5% Calculation:Digits: 2, 2Multiplier: Red = x 100Result: $22 \times 100 = 2200 \Omega = 2.2 k\Omega$. 12.2 Frequently Asked Questions about 2.2k Ohm Resistor1. What does a 2.2k resistor do?It is commonly used in voltage dividers, particularly with LDRs (Light Dependent Resistors) to read ambient light levels with a microcontroller. 2. Calculating Current for a 1/2 Watt 2.2k ResistorIf you have a 1/2 Watt (0.5W) resistor, the maximum current it can handle is calculated using the power formula $P = I^2 \times R$.Rearranging for current ($I$):$I = \sqrt{P / R}$$I = \sqrt{0.5 / 2200}$$I \approx 0.015$ AmperesConclusion: A 2.2kΩ 1/2W resistor can safely handle approximately 15 milliamperes (mA). XIII Resistor Color Code Calculator13.1 4 Band Resistor Color Code CalculatorNeed to double-check your work? Use this tool to instantly decode 4-band axial lead resistors. Open 4 Band Resistor Color Code Calculator13.2 5 Band Resistor Color Code CalculatorFor high-precision 5-band resistors, use the calculator below: Open 5 Band Resistor Color Code Calculator 13.3 6 Band Resistor Color Code CalculatorIncludes the 6th band for Temperature Coefficient (PPM). Open 6 Band Resistor Color Code Calculator

The heart of this circuit is the LM3914 from national semiconductors. The LM3914 can sense voltage levels and can drive a display of 10 LEDs in dot mode or bar mode. The bar mode and dot mode can be externally set and more than one ICs can be cascaded together to gat an extended display. The IC can operate from a wide supply voltage (3V to 25V DC). The brightness of the LEDs can be programmed using an external resistor. The LED outputs of LM3914 are TTL and CMOS compatible.In the circuit diagram LEDs D1 toD10 displays the level of the battery in either dot or bargraph mode. Resistor R4 connected between pins 6,7 and ground controls the brightness of the LEDs. Resistors R1 and POT R2 forms a voltage divider network and the POT R2 can be used for calibration.The circuit shown here is designed in order to monitor between 10.5V to 15V DC. The calibration of the circuit can be done as follows. After setting up the circuit connect a 12V DC source to the input. Now adjust the 10K POT to get the LED10 glow (in dot mode) or LEDs up to 10 glow (in bar mode). Now decrease the voltage in steps and at 10.5 volts only LED1 will glow. Switch S1 can be used to select between dot mode and bar graph mode. When S1 is closed, pin9 of the IC gets connected to the positive supply and bar graph mode gets enabled. When switch S1 is open pin9 of the IC gets disconnected to the positive supply and the display goes to the dot mode.With little modification the circuit can be used to monitor other voltage ranges. For this just remove the resistor R3 and connect the upper level voltage to the input. Now adjust the POT R2 until LED 10 glows (in dot mode). Remove the upper voltage level and connect the lower level to the input. Now connect a high value POT (say 500K) in the place of R3 and adjust it until LED1 alone glows. Now remove the POT, measure the current resistance across it and connect a resistor of the same value in the place of R3. The level monitor is ready.Circuit diagram of battery level indicator using LM3914.Cascading two LM3914.Two or more LM3914 ICs can be cascaded together to get an extended display. The schematic of two LM3914 ICs cacaded together to get a 20 LED voltage level indicator is shown belowFew other battery level related circuits that you may like.1.Simple battery level indicator : This circuit can be used for monitoring the level of 3V batteries. The circuit is based on MN13811G from Panasonic. MN13811G is a CMOS  voltage detector IC that can be used a variety of voltage monitoring applications. In the circuit LED D1 will flash when ever the battery voltage drops below 2.4 volts.2.3 LED battery level indicator : A 3 LED battery level indicator that can be used for monitoring the voltage level of 12V automobile battery is shown here. Three states of the battery ie; below 11.5V, between 11.5 and 13.5 and above 13.5 are shown by the glowing of LEDs.3. Flashing battery monitor : This circuit can be used for monitoring the voltage level of 6 to 12V batteries. The circuit is based on transistors and the voltage level at which the LED starts flashing can be adjusted by using a potentiometer.

Inside a secretive AI nonprofit backed by Elon Musk and other Silicon Valley figures, a handful of robots designed to help out in warehouses are gradually learning how to do useful household chores.OpenAI, which was created to do basic AI research, is reprogramming robots developed by Fetch Robotics, a company that supplies warehouse automation hardware. Researchers at OpenAI are equipping the robots with software that lets them train themselves through trial and error. The effort reflects a bet that innovations in software and machine learning, rather than breakthroughs in hardware, are the way to give robotics remarkable new capabilities. Fetch makes a range of robots for warehouses, including systems that follow workers around a building, carrying items dropped into a basket. OpenAI is using a system that features a mobile base but also 3-D depth sensors, a 2-D laser scanner, and a robotic arm with seven degrees of freedom. In April, OpenAI recruited Pieter Abbeel, a professor at the University of California, Berkeley, and a leading expert on robot learning. Abbeel has shown how robots can use a machine-learning approach called deep reinforcement learning to acquire completely new skills that would be hard to program by hand, such as folding towels or retrieving items from a refrigerator. Google DeepMind, an AI subsidiary based in the U.K., uses this technique to get computers to play computer games at a superhuman level.Abbeel’s robots learn tasks from scratch, using a neural network that receives sensor input and controls physical movement. The network adjusts its parameters automatically as it inches closer to its goal. A robot might try thousands of grips, for instance, in the process of learning how to hold a certain object. “If this goal can be achieved, then there will be economic and industrial benefits,” says Marc Deisenroth, an expert on reinforcement learning at Imperial College London. “Imagine a Roomba not only cleaning your floor but also doing the dishes, ironing the shirts, cleaning the windows, preparing breakfast.”Deisenroth says using off-the-shelf robots could drive costs down. “Currently, the software seems to be the bottleneck,” he adds. “However, independent of this, better hardware could also lead to substantial improvements.” Soft manipulators and elastic feet similar to a monkey’s feet are concepts that researchers have started working on, he says.Some manufacturers, including the Japanese company Fanuc, are testing reinforcement learning as a way to train industrial robots quickly in new tasks such as learning to grasp unfamiliar objects. When many robots work in parallel, the training time required is reduced accordingly . Robot researchers at Google are testing similar learning techniques.“Moving away from having to program robots by hand by endowing robots to learn autonomously is a key element for the future of robotics,” says Jens Kober, an expert on robot learning at Delft University of Technology in the Netherlands. Kober says having robots share the information they have learned will be crucial.While robots such as those made by Fetch are finding their way into many factories and warehouses, domestic robot helpers remain the stuff of science fiction. Performing seemingly simple tasks like washing dishes or folding laundry in a messy home setting is incredibly hard for a machine. A robot programmed the conventional way can easily be thrown off by an unfamiliar object or a slight variation in lighting.OpenAI confirmed that it is working with the robots from Fetch, but it declined to comment further. Melonee Wise, the company’s founder, couldn’t be reached for comment.OpenAI was created by Musk and a handful of well-known (and well-heeled) Silicon Valley entrepreneurs, including investor Peter Thiel, Y Combinator president Sam Altman, and the incubator’s cofounder Jessica Livingston. The nonprofit’s backers have committed $1 billion in funding to the project, and it is being led by Ilya Sutskever, a prominent AI researcher who left Google to join the project, and Greg Brockman, an early employee at the high-profile digital payment company Stripe.While OpenAI has committed to making the technology it develops publicly available, it could certainly benefit companies backed by Musk and Thiel, as well as those emerging from Y Combinator.Produced by Will Knight  

Ⅰ IntroductionA shunt is an electrical device that creates a low-resistance route for a current to flow through. This allows the current to flow to a different part of the circuit. Ammeter shunts and current shunt resistors are two terms for shunts. A shunt resistor is used to measure alternating or direct electric current. The voltage drop across the resistor is used to determine this. Shunt resistors were once used to describe a resistor connected in parallel to an ammeter as a shunt to increase the current measurement range, but in recent years, all resistors used to detect circuit current have been referred to as shunt resistors (current sense shunt resistor). This vedio shows a shunt resistor CatalogⅠ IntroductionⅡ What Does a Shunt Resistor Do?Ⅲ How Does a Shunt Resistor Work?Ⅳ How to Measure Current by a Shunt Resistor?Ⅴ Position of the Shunt Resistor in the Circuit When Measuring CurrentⅥ How to Select a Shunt Resistor?6.1 How to Calculate Shunt Resistance?6.2 Shunt Resistor ParametersⅦ How to Wire a Shunt Resistor?Ⅷ Frequently Asked Questions about Shunt Resistor Ⅱ What Does a Shunt Resistor Do?The electrical shunt is a device that creates a low-resistance route that allows electricity to travel through or be redirected past a defined point in a circuit. Some meters have built-in precision current shunts that allow measurements in terms of DC and Watts to be taken. Electrical shunts can also be used to measure the flow of DC. The formula for Ohm's law is as follows: V = I × R This equation applies to the voltage (V) created across the resistance (R in ohms) as a function of the resistance and the current (I in amps) flowing through it. A current shunt with a resistance of 0.002 ohms and a current of 30 amps, for example, will generate 0.002 x 30 = 0.06 volts or 60 millivolts (milliVolts). By including a current shunt into a measurement circuit, you can determine the voltage drop across the shunt. The calculation of current measurement using Ohm's law will be possible thanks to the assessment of current shunt resistance. The current shunt resistance can also be calibrated using Ohm's law. Shunt resistors are commonly used in the following applications:Current circulating through a battery is measured, and power output is monitored.Before the signal reaches the circuit elements, high-frequency noise is redistributed (this requires a shunt with a capacitator).Installation in a DC connects the container with a negative conductor connecting the batteries to the inverter.Control equipment, such as battery chargers and power sources, provides overload protection. Ⅲ How Does a Shunt Resistor Work?The technological limits of a shunt resistor differ from those of a conventional resistor. Shunt resistors allow for high precision while maintaining a low ohmic value. To reach such great precision, a Kelvin connection is recommended. This connection eliminates difficulties like lead sensitivity and resistance. The value of a shunt resistor can be influenced by several reversible and irreversible causes. Long-term stability and irreversible change in resistance are ensured by the accompanying mechanical, electrical, and thermal stresses. The Temperature Coefficient of Resistance (TCR) is measured in ppm/ and represents the drift caused by the transistor cooling or heating due to changes in ambient temperature. The Power Coefficient of Resistance (PCR) or ppm/W is used to express the amount of power that the resistor must dissipate. Electrical shunts are commonly used to safeguard the speed controller from a load that consumes too much current or to limit the motor's speed. By disconnecting the shunt from the sense line, the controller's speed can be increased. After that, the sense line must be linked to the ground. Because there will be no voltage drop, the speed controller will generate the maximum amount of power feasible. However, if the load on the controller transistors is too great, this could be dangerous. A high-precision current shunt can also be utilized for equipment bench testing. This current shunt can be used in conjunction with a voltmeter to determine the amount of current flowing through the circuit. The use of a sensitive voltmeter ensures a high level of safety in the measurement of greater currents than can be achieved with a regular multimeter. Ⅳ How to Measure Current by a Shunt Resistor?An ammeter is a device that measures electric current. The voltage drop across a precision resistor with a known resistance is measured by most modern ammeters. Ohm's law is used to calculate current flow:  To measure current, most ammeters feature a built-in resistor. When the current is too high for the ammeter, however, a different configuration is required. The solution is to connect the ammeter to a precise shunt resistor in parallel. Ammeter shunt is a name that is sometimes used to describe this sort of resistor. This is usually a low resistance manganin resistor with great accuracy. Only a small (known) amount of the current travels through the ammeter after it is divided between the shunt resistor and the ammeter. The remaining current travels through the shunt resistor, bypassing the ammeter. Large currents can still be measured this way. The actual amperage can be measured by accurately scaling the ammeter. The greatest amperage that can be measured using this arrangement is theoretically limitless. However, the measurement device's voltage rating must not be exceeded. As a result, the maximum current multiplied by the ammeter resistance value cannot exceed the voltage rating. To minimize circuit interference, the ammeter resistance should be as low as feasible. A smaller ammeter, on the other hand, creates a smaller voltage drop, which results in a lesser resolution. Example of calculationA series resistor in an ammeter, for example, is a shunt resistor with a resistance of 1 mΩ. A voltage drop of 30 mV is observed across the resistor after it is inserted in a circuit. The current is equal to the voltage divided by the resistance in this case, or:I=V/R=0.030/0.001=30A. With the resistance value unknown and the voltage and current known, the same calculation might be performed. This is how shunt resistance is measured. Ⅴ Position of the Shunt Resistor in the Circuit When Measuring CurrentA.To eliminate the common-mode voltage, the shunt is frequently put on the grounded side. However, there are certain drawbacks.B.The common-mode voltage may be too high for the ammeter in this arrangement. Position of the Shunt Resistor in the Circuit The placement of the shunt resistor in the circuit must be carefully considered. When the circuit and the measurement instrument share a common ground, the shunt is frequently put as close to the ground as practicable. The rationale for this is to safeguard the ammeter from excessive common-mode voltage, which could harm the instrument or cause incorrect results. One downside of this configuration is that leakage currents through the shunt may go undetected. To protect the instrument, the shunt must be isolated from the ground or incorporate a voltage divider or an isolation amplifier if it is put in the ungrounded leg. Other options include employing a Hall Effect sensor instead of directly attaching the measurement instrument to the high voltage circuit. Current shunts, on the other hand, are frequently cheaper. Ⅵ How to Select a Shunt Resistor?Shunt resistors are a type of resistor that creates a low resistance route. Because of their low resistance, they are commonly employed to detect high currents. Many applications necessitate current measuring. Overcurrent protection, 4-20mA systems, battery chargers, high-brightness LED control, H-bridge motor control, and metrology, for example, all require current monitoring. Shunt sensors are simpler to develop and less expensive than magnetic current sensors. They do not, however, afford any seclusion. A Rogowski coil, also known as a Hall effect sensor, is a noninvasive measurement in which the detecting circuitry is not electrically coupled to the monitored system and subsequently isolated. 6.1 How to Calculate Shunt Resistance?Shunt resistors have different technological limits than normal resistors. They have a low ohmic value and are high-precision resistors (they can be expressed in microOhm when several hundreds of Amper currents must be measured). Because accuracy is crucial, current sensing is best accomplished via a Kelvin connection (or four-terminal connection), which eliminates the undesired effects of lead resistance and temperature sensitivity. Four-terminal connection equation A shunt resistor's value can be changed by a variety of causes, which are divided into reversible and irreversible effects. A change in resistance that is irreversible owing to mechanical, electrical, or thermal stresses is referred to as long-term stability. There are two fundamental components to reversible effects:Temperature Coefficient of Resistance (TCR): TCR is measured in parts per million and describes how the resistor drifts as the ambient temperature changes.The Power Coefficient of Resistance (PCR) is a unit of measurement for the amount of power a resistor must dissipate. It is given in ppm/W. 6.2 Shunt Resistor ParametersThe thermal EMF is an important metric for shunt resistors that isn't as critical for ordinary resistors. A voltage changeable with temperature appears at the junction of two different conducting materials (explaining why it's termed thermal EMF or thermocouple effect and expressed in µV/). An intermetallic junction's rate of change of voltage with temperature is a function of the metallic combination. Depending on whether side of the combination is regarded as the input, the voltage produced is either positive or negative. All resistors are assumed to be soldered to copper at some point, and copper becomes the reference metal. Some Thermal EMF values are shown in the table below. Table 1: Thermal EMF of the Metal vs. CopperMetal / AlloyThermal EMF vs copper in μV/°CEvanohm2Cupron-45Manganin-3Zeranin-1.3Nickel-22Gold0.2Silver-0.2Aluminum-4 Table 2. TCR, ppm/  of various Resistor Element MaterialsTemperature range-55°C to +25°C0°C to +25°C+25°C to +60°C+25°C to +125°CManganin5010-5-80Zeranin20±2.5±510Evanohm52.5-2.5-5Foil (Vishay proprietary)-1-0.30.31Thin Film-10-5510Thick Film-100-2550100 Manganin is the preferred material for shunts with exposed blades based on thermal EMF, TCR, and cost. Zeranin, a cousin of Manganin with a lower temperature coefficient, is used to make shunts with exposed parallel wires. Evanohm, which has a near-zero temperature coefficient and a high sensitivity to strain, is commonly used to make shunts contained in heat sinks. Ⅶ How to Wire a Shunt Resistor?First, read and follow any manufacturer's instructions. It will be required to make sure that the ammeter and the shunt can handle the same mV levels. The shunt must then be connected to the negative connection that runs from the battery bank to the electrical circuits. Following the negative lead from the battery to the circuits or fuse box will reveal this. Adjust the negative connections on the battery to the corresponding side of the battery and shunt if you want to measure the current consumed by the connected device and supplied by the alternator. The other side of the shunt should be linked to the battery's negative terminal with a sufficiently thick cable. The shunt resistor must be installed in a location where there is no possibility of shorting cables. The negative cables can be shortened to make the installation process easier. It is also necessary to drill a suitable hole for the ammeter to mount on the panel. The hole must be large enough to connect the meter firmly. The plus and minus pins on the connection between the leads and the DC  or voltage should be properly fitted. You must also confirm that the meter is correctly set (the current can be measured in AC, DC, ohms etc). The wiring procedure should start with a simple check to confirm that the shunt is connected to the load in series. You'll also need to hook up a battery pack and make sure it's linked to the right side of the shunt. The wiring from the shunt should then be fed to the load. The ammeter and the ground should not be connected in any way. The ammeter, on the other hand, should be wired in parallel with the shunt, with the shunt connected to the load in series. The powering of the circuit should be the first step in measuring the current or voltage. After that, you can take the meter reading. When measuring the level of resistance, however, you should not turn on the electricity. Ⅷ Frequently Asked Questions about Shunt Resistor1.What is the meaning of shunt resistor？A resistor having a very low value of resistance such type of resistor is called shunt resistance. The shunt is used in the galvanometer for measuring the large current. It is connected in parallel to the circuit of the galvanometer. 2.Why is it called a shunt resistor?In electronics, a shunt is a device that creates a low-resistance path for electric current, to allow it to pass around another point in the circuit. The origin of the term is in the verb 'to shunt' meaning to turn away or follow a different path. 3.Why a shunt resistor is connected in parallel?A shunt resistor is connected in parallel to the galvanometer so as to keep the resistance low. Such low resistance galvanometer is used in series with the circuit to measure the strength of current through the circuit. 

Ⅰ IntroductionA Colpitts oscillator is one of several designs for LC oscillators, which employ a combination of inductors (L) and capacitors (C) to produce an oscillation at a specific frequency. It was invented in 1918 by American engineer Edwin H. Colpitts. The voltage divider made up of two capacitors in series across the inductor serves as feedback for the active device in the Colpitts oscillator.   CatalogⅠ IntroductionⅡ What a Colpitts Oscillator Contains?Ⅲ How the Colpitts Oscillator Works?Ⅳ Colpitts Oscillator vs Hartley OscillatorⅤ Types of Colpitts Oscillator5.1 Common Base Colpitts Oscillator5.2 Common Emitter Colpitts Oscillator5.3 Buffered Colpitts OscillatorⅥ Advantages of Colpitts OscillatorⅦ Applications of Colpitts OscillatorⅧ ConclusionⅨ Frequently Asked Questions about Colpitts OscillatorⅡ What a Colpitts Oscillator Contains?The Colpitts circuit, like other LC oscillators, is made up of a gain device (such as a bipolar junction transistor, field-effect transistor, operational amplifier, or vacuum tube) with its output connected to its input in a feedback loop containing a parallel LC circuit (tuned circuit) that serves as a bandpass filter to set the oscillation frequency. The amplifier's input and output impedances will be different, and these must be linked into the LC circuit without overdamping it. Ⅲ How the Colpitts Oscillator Works?The Colpitts oscillator is commonly used in RF applications, with a frequency range of 20KHz to 300MHz. The capacitive voltage divider configuration in the tank circuit serves as the feedback source in the Colpitts oscillator, and this arrangement provides superior frequency stability than the Hartley oscillator, which uses an inductive voltage divider system for feedback. The circuit diagram of a typical transistor-based Colpitts oscillator is shown below. Colpitts oscillator The resistors R1 and R2 in the circuit schematic provide a voltage divider biasing for the transistor. The transistor's collector current is limited by the resistor R4. The input DC decoupling capacitor is Cin, and the output decoupling capacitor is Cout. The emitter resistor, Re, is used to ensure thermal stability. The emitter by-pass capacitor is denoted by Ce. The emitter by-pass capacitor's job is to keep the amplified AC signals from crossing Re. If the emitter by-pass capacitor is missing, the amplified AC signal will drop across Re, causing the transistor's DC biasing conditions to change, resulting in lower gain. The tank circuit is made up of capacitors C1, C2, and inductor L1. Tank circuit in a Colpitts oscillator When the power source is turned on, the capacitors C1 and C2 begin to charge. They start discharging through the inductor L1 when they are completely charged. The electrostatic energy stored in the capacitors is transmitted to the inductor as magnetic flux when the capacitors are fully drained. The inductor begins to discharge and the capacitors are re-charged. Oscillation is caused by energy being transferred back and forth between capacitors and inductors. The voltage across C2 is in phase opposite that of C1, and the voltage across C2 is sent back to the transistor. The enhanced feedback signal at the transistor's base emerges across the collector and emitter. The transistor compensates for the energy lost in the tank circuit, maintaining the oscillations. One 180° phase shift is produced by the tank circuit, and the other 180° phase shift is produced by the transistor. That means the input and output are in phase, and positive feedback requires to keep oscillations going for long periods. The equation below can be used to calculate the frequency of the Colpitts oscillator's oscillations. Where L is the inductance of the tank circuit's inductor and C is the effective capacitance of the tank circuit's capacitors. The effective capacitance of the serial combination C= (C1C2)/(C1+C2) if C1 and C2 are independent capacitances. The Colpitts oscillator can be made variable by utilizing ganged variable capacitors in place of C1 and C2. Ⅳ Colpitts Oscillator vs Hartley OscillatorThe Colpitts oscillator is extremely similar to the Hartley oscillator, however they are constructed differently. The Colpitts oscillator employs a single inductor in parallel with two capacitors in series, whereas the Hartley oscillator utilizes the exact opposite, one single capacitor in parallel with two inductors in series. In high-frequency operation, the Colpitts oscillator is more stable than the Hartley oscillator. Colpitts Oscillator vs Hartley Oscillator In high-frequency operation, the Colpitts oscillator is an ideal choice. It can generate output frequencies in the Megahertz and Kilohertz ranges. Ⅴ Types of Colpitts Oscillator5.1 Common Base Colpitts OscillatorA typical Colpitts oscillator design is shown below. The Colpitts LC tank circuit operates similarly to the Hartley oscillator, however it only has a single inductor and two capacitors. Instead of the tapped inductor used in the Hartley, the capacitors create a single 'tapped' capacitor. The total capacitance in series (CTOT) of the two capacitors (connected in series) is calculated as follows: common base Colpitts oscillator The total capacitance required for the tank circuit to achieve parallel resonance at the specified frequency is given. The oscillation frequency is calculated using the same formula as the Hartley oscillator. However, in this case, the number C is the sum of the values C2 and C3 in order (CTOT). C2 and C3's values are chosen so that their ratio delivers the required proportion of feedback signal. The ratio of voltages across two capacitors in series, on the other hand, is inversely proportional to the ratio of their values, implying that the smaller capacitor has a higher signal voltage across it. The fundamental advantage of the Colpitts design is that the single inductor in the tuned circuit eliminates any mutual inductance between two coils, where the alternating magnetic field generated up around one inductor drives a current into the inductor of the other coil. This alters the resonance frequency of the tuned circuit by changing the total inductance of the coils. 5.2 Common Emitter Colpitts OscillatorThe Colpitts analog of the Common Emitter Hartley Oscillator is shown below.                              common emitter Colpitts oscillator It employs a common emitter amplifier, and because the tuned (tank) circuit tapping point is connected to the ground in this design, the tank circuit generates anti-phase waves at the top and bottom of L2, ensuring proper phase relationships for positive feedback between collector and base. The feedback is delivered to the base via C1, which also functions as a DC block, preventing the greater voltage on L1 from causing the base bias voltage to be thrown off. The supply rail (+Vcc) is connected to the tank circuit (L2, C2, and C3) through L1. Because the DC supply is significantly decoupled by huge capacitors in the DC Power supply, if the tank circuit were connected directly to the supply, there would be no anti-phase AC signal present at the top of the tank circuit. As a result, between the tuned circuit and the supply, an RF choke (L1) with a high impedance at the oscillation frequency is provided. This permits the development of a signal voltage across L1 for feedback purposes. Automatic class C bias is utilized, with the emitter only partially disconnected by a small amount of C5 to provide the previously mentioned "slide bias." The Colpitts oscillator, like the Hartley, can produce an excellent sine wave shape and has the added benefit of improved stability at very high frequencies. It's easy to spot because it's always got a "tapped capacitor" on it. The fact that any load placed on the output by circuits that the output is supplying essentially inserts a dampening resistance across the tank circuit complicates the design of a sine wave oscillator. This can have an adverse influence on both the wave shape and frequency stability of the oscillator waveform, as well as lowering the amplitude of the oscillator output by lowering the Q factor of the tuned tank circuit. 5.3 Buffered Colpitts OscillatorAs demonstrated below, feeding the oscillator output into an emitter follower buffer amplifier is a standard technique. buffered Colpitts oscillator TR1's load impedance has been changed to the RF choke, and the tank circuit is now isolated from TR1 by two DC blocking capacitors, C1 and C4. As a result, instead of a tuned amplifier, this variant of the Colpitts oscillator uses a tuned feedback channel. The emitter follower stage (R4, TR2 and R5) has a very high input impedance, which has no effect on the oscillator, and a very low output impedance, which allows it to drive loads with impedances as low as a few tens of ohms. Variations in supply voltage can also affect the frequency stability of oscillators. When good frequency stability is required, it is typical to use a stabilized power supply. Extra decoupling capacitors may be required for oscillator supplies to reduce undesired 'noise.' Automatic class C bias, which is given in this circuit by only partially disconnecting the emitter of TR1 by C5, is generally used to achieve stable amplitude. Ⅵ Advantages of Colpitts OscillatorThe Colpitts oscillator may produce very high-frequency sinusoidal pulses.It can tolerate extreme heat and cold.There is a lot of frequency stability.Both variable capacitors can be used to change the frequency.A small number of components is all that is required.Over a certain frequency range, the output amplitude remains constant.The Colpitts oscillator was created to address the shortcomings of the Hartley oscillator and is known to have no unique flaws. As a result, a Colpitts oscillator has a wide range of uses. Ⅶ Applications of Colpitts OscillatorThe Colpitts oscillator is mostly employed for fixed frequency generation due to the challenges in achieving a smooth variation of inductor and capacitor.The Colpitts oscillator is most commonly found in mobile phones and other radio frequency-controlled communications devices.The Colpitts oscillator is a great choice for high-frequency oscillation. Colpitts Oscillator is used in high-frequency oscillator-based systems.Colpitts Oscillator is utilized in a few applications where continuous and undamped oscillation is required as well as thermal stability.For applications that require a broad range of frequencies with minimal noise.Colpitts oscillator is used in a variety of SAW-based sensors.The Colpitts oscillator is used in a variety of metal detectors.A Colpitts oscillator is used in frequency modulation radio frequency transmitters.It has a wide range of uses in both military and commercial items.Signal masking-related chaotic circuits are also required in microwave applications Colpitts oscillator in various frequency ranges. Ⅷ ConclusionTo summarise, the Colpitts Oscillator consists of a parallel LC resonator tank circuit whose feedback is achieved by way of a capacitive divider. The Colpitts oscillator exists in several forms like most oscillator circuits, and the most common form is the transistor circuit. The tank sub-center circuit's tap is made at the junction of a "capacitive voltage divider" network, which feeds a fraction of the output signal back to the transistor's emitter. The 180o phase shift produced by the two capacitors in series is inverted by another 180o to produce the requisite positive feedback. The resonance frequency of the tank circuit determines the oscillation frequency, which is a purer sine-wave voltage. Ⅸ Frequently Asked Questions about Colpitts Oscillator1.What is the use of Colpitts oscillator?It is used for generation of sinusoidal output signals with very high frequencies. The Colpitts oscillator using SAW device can be used as the different type of sensors such as temperature sensor. As the device used in this circuit is highly sensitive to perturbations, it senses directly from its surface. 2.What is the basic principle of oscillator?There are many types of electronic oscillators, but they all operate according to the same basic principle: an oscillator always employs a sensitive amplifier whose output is fed back to the input in phase. Thus, the signal regenerates and sustains itself. This is known as positive feedback. 3.What is meant by Colpitts oscillator?A Colpitts oscillator, invented in 1918 by American engineer Edwin H. Colpitts, is one of a number of designs for LC oscillators, electronic oscillators that use a combination of inductors (L) and capacitors (C) to produce an oscillation at a certain frequency. 

ⅠIntroduction Resistor is commonly used in our daily life. There are all kinds of resistor in a vehicle. As we know ,the air conditioning is very important for a car . One of the most essential components is blower motor resistor. This article embodies basic knowledge about blower motor resistor.Figure1： the location of Blower Motor Resistor ⅠIntroductionⅡDefinition and Function of Blower Motor Resistor2.1 Definition of Blower Motor Resistor2.2 Function in a CarⅢ How the Blower Motor Resistor Works？Ⅳ Symptons of Faulty Blower Motor ResistorⅤ Blower Motor Resistor TestⅥ How to Replace Blower Motor Resistor6.1 DIY Jobs Related to the Blower Motor Resistor6.2 Details of Replacing Blower Motor ResistorⅦ Frequently Question Asked about Blower Motor Resistor ⅡDefinition and Function of Blower Motor Resistor 2.1 Definition of Blower Motor ResistorThe heating and air conditioning system in your vehicle is made up of many parts that work together to produce the desired air temperature. Some of these parts will (hopefully) last the life of your vehicle, but others will wear out and need to be replaced.The blower motor resistor is a small electrical component that, if it fails, can cause noticeable problems with the air in the passenger compartment. Understanding how it works can assist you in identifying the symptoms of a faulty resistor.This vedio shows a circuit of a blower motor  2.2 Function in a CarA blower motor is a device that drives the fan in a car's heating and air conditioning system. It's usually found inside the dash, on the opposite side of the steering wheel, or on the firewall inside the engine compartment. A blower motor resistor, also known as a blower motor control module, is the component that regulates the speed of the blower motor.An electronic blower motor control module is fixed in cars with automatic climate control systems and vehicles where the blower speed can be gradually adjusted.  Figure2: the control module The blower motor resistor or control module is usually installed inside one of the ducts in the HVAC system, close to the blower motor, in most modern vehicles. This is done so that the resistor or control module can be cooled by passing air. A blower motor resistor was installed on the firewall of some older vehicles, with access from under the hood. Ⅲ How the Blower Motor Resistor Works？Blower motor resistor diagram depicts how the blower motor resistor is connected in a typical automobile. The resistor is bypassed in this car at the highest "4" fan speed setting, and the blower motor is powered directly by the fan switch. As a result, even if the resistor is faulty, the blower motor in some vehicles may continue to operate at a "High" speed.The fan switch is set to "1" in this diagram, so the blower motor current is reduced by three resistors (R2 + R3 + R4) connected in series. The flow of current is depicted in blue and red.Two resistors are connected in series when the setting is 2.  Whereas, in setting "3," there is only one resistor. When resistance is added to an electric circuit, the current in the circuit is reduced. When multiple resistors are connected in series, the total resistance rises and equals the sum of the individual resistances. Figure3: how the blower motor resistor works  Ⅳ Symptons of Faulty Blower Motor ResistorA faulty blower motor resistor can disrupt the operation of the entire heating and cooling system. A bad or failing blower motor resistor will usually cause a few symptoms that will alert the driver to a potential problem. It is critical to understand the symptoms of a faulty motor resistor. 1. The blower motor is stuck at one speed.A blower motor that is stuck on one setting is a common symptom of a faulty blower motor resistor. The blower motor resistor is the component directly responsible for controlling the fan speed of the blower motor. If the resistor shorts or fails, the blower motor may become stuck at one fan speed. The heating and air conditioning systems may continue to operate at one speed, but the resistor has to be replaced before full functionality can be restored. 2. The blower motor does not operate in certain settings.A blower motor that does not function in certain settings is another common symptom of a faulty blower motor resistor. If the internal components of the blower motor resistors fail, the blower motor may malfunction or not function at all on one or more of the settings. Perhaps, a faulty blower motor switch can lead to the same situation, so a proper diagnosis is highly recommended if you are unsure of the problem. 3.There is no air coming from the vehicle's vents.Another sign of a faulty blower motor resistor is the absence of any air from the vehicle's vents. Power to the blower motor is routed through the blower motor resistor, so if it fails or has any problems, power to the motor can be cut off. A blower motor that is not powered will not have the capacity to produce any air pressure, leaving the heating and air conditioning system with no air coming from the vents.Because the blower motor resistor is the component directly responsible for powering the blower motor, when it fails, dangerous problems with the blower motor and the heating and air conditioning system can occur. If your vehicle exhibits any of the symptoms listed above, or you suspect that your blower motor resistor is malfunctioning, have it inspected by a professional technician, such as one from YourMechanic, to determine if the component needs to be replaced. Ⅴ Blower Motor Resistor TestFirstly, if the blower motor does not work at all, it is necessary to test the motor. When the blower motor is turned on, the voltage at the blower motor connector is typically measured. If there is a voltage at the motor (at least 4-6 Volts at low speed and 12 Volts at high speed), but the motor does not run, the motor is defective or jammed. Voltage testing of the blower motor The voltage at the blower motor is being tested. If there is a voltage at the motor (at least 4-6 Volts at low speed and 12 Volts at high speed), but the motor does not run, the motor is defective.Figure4: how to test the blower motor resistor Leaves, twigs, nuts, and pieces of a ripped cabin filter can jam the blower motor's blade. This is a common occurrence in many automobiles.The entire blower motor circuit, beginning with a fuse, has to be tested if the motor is in the case of no voltage. See also: how to test a fuse in a car.If a blower motor fails, it must be replaced. Depending on the vehicle, the cost of replacing the blower motor ranges from $320 to $650. In many cars, the blower motor is located behind the glove box and is held in place by 3-4 screws. In others, it may be located inside the dash (as in the Mazda 5), making replacement difficult. Ⅵ How to Replace Blower Motor Resistor6.1 DIY Jobs Related to the Blower Motor ResistorWhile you're under the hood working around the HVAC housing, here are some related tasks you should complete for preventative maintenance or to avoid future HVAC system problems.Take out and clean the blower motor fan.Replace the cabin air filter. Figure5: the blower fan 6.2 Details of Replacing Blower Motor ResistorThe following are the simple steps to replacing a blower motor resistor: 1.Locate the Blower Motor ResistorObviously, the first thing you had better do is locate the blower motor resistor so that you determine which component will be taken out. It is directly next to the blower motor. The latter, on the other hand, is commonly found underneath the passenger side dash or in the engine compartment. 2.Take out the Blower Motor ResistorRemove the blower motor resistor now that you know where it is. To begin, remove the components surrounding the blower motor resistor, including the pigtail connected to the AC and the blower motor cooling duct. You can now easily access the blower motor resistor at this point.All that remains is to unscrew the bolts that hold the blower motor resistor in place. Using a ratchet with a short extension, tighten the screw. Once the bolts are taken out, all that remains is to remove the blower motor resistor. 3.Disconnect the WiresAfter removing the blower motor resistor, cut the wires that connect to the component. Cut the wires with a stripper or scissors designed for cutting through wires. 4.Install the New Blower ResistorApply dielectric grease to the housing of the blower motor resistor before proceeding with the installation. It will keep water out of the vehicle, which is a common issue when driving off-road. Apply a coating around the plastic to create a seal that will protect the component.Replace the blower motor resistor in the same location where it was previously removed. Replace the screws to secure them in place. Connect the pigtail when you are finished with the job. However, there are some cases in which the pigtail has already worn out. Proceed to the next step if this is the case.Disconnect the old wires and reconnect the new ones. Because the wires are probably color-coded, this should be simple. Connect the new wires with the connectors. Return the pigtail to its original position, and you fulfill the task.Ⅶ Frequently Question Asked about Blower Motor Resistor1.What does a resistor do for a blower motor?Blower resistors are resistors which are used to control the fan speed of automotive blowers. The fan speed can be changed either by switching the blower resistor resistance mechanically using a rotating lever, or electronically by the air conditioning system. 2.Why do blower motor resistors fail?In most cases, a blower motor resistor fails due to corrosion or overheating. Sometimes, the mechanical resistance to the motor rotation causes an excessive electric current that can overheat and prematurely damage the blower motor resistor. 3.Can you fix a blower motor resistor?The resistor module is easy and inexpensive to replace. It's then typically installed in the ductwork, near the car blower—either under the dash or under the hood. (Refer to a service manual to locate yours.) Purchase a new resistor module at the auto parts store (usually less than $25). 4.Can you drive with a bad blower motor?A bad heater blower motor will not affect the safety of your car, with the possible exception of you not being able to clear the windshield of snow, ice, or condensation if the defrosters don't work. But you won't be comfortable inside your car, especially during the cold of winter and the heat of summer. 5.How do I know if my blower motor has power?Check for power at the motor itself. Using a test light or a multimeter set on volts, unplug the blower motor. Keeping the black lead on a good ground, usually a bolt on the engine block, and the blower switch turned on, use the red lead to probe the plug that usually attaches to the blower motor.