The Kynix Components

74LS32 is a Dual Input OR Gate with Quad package.  It contains four independent gates, each performing the logic OR function. Each gate has two inputs, which is why it is called Quad 2-Input OR Gate. Logic level gates like 74LS32 and flip-flops play a vital role in digital electronics. This blog is a brief introduction to 74LS32  about its pinout, features, equivalents, and how to use this device, and so on. This is a video introducing 74LS32's truth table.Catalog74LS32 Pinout74LS32 Features74LS32 Parameter74LS32 EquivalentsHow to Use 74LS32 OR Gate IC?74LS32 Applications74LS32 PackageComponent DatasheetFAQ74LS32 Pinout Pin NumberPin NameDescription1,4,9,12OR Gate Input pin (A)First Input pin for the OR gate2,5,10,13OR Gate Input pin (B)Second Input pin for the OR gate3,6,8,11OR Gate Output pin (Y)Output pin for the OR gate7GroundConnect to the ground of the circuit.14Vcc (Vdd)Used to power the IC. Typically +5V is used74LS32 FeaturesDual Input OR Gate – Quad PackageSupply Voltage: 5 to 7V Input Voltage: 5 to 7VOperating temperature range = -55°C to 125°CAvailable in 14-pin SOIC package74LS32 ParameterManufacturer:Texas InstrumentsSeries:74LSPackaging:TubePart Status:ActiveLogic Type:OR GateNumber of Circuits:4Number of Inputs:2Features:-Voltage - Supply:4.75V ~ 5.25VCurrent - Output High Low:400µA 8mALogic Level - Low:0.8VLogic Level - High:2VMax Propagation Delay @ V Max CL:22ns @ 5V 15pFOperating Temperature:0°C ~ 70°CMounting Type:Through HoleSupplier Device Package:14-PDIPPackage / Case:14-DIP (0.300" 7.62mm)Base Part Number:SN74LS3274LS32 EquivalentsEquivalent for 74LS32  : CD4071Other  Logic Gates:  74LS00, 74LS08, 74LS02, 74LS04, 74HCT04How to Use 74LS32 OR Gate IC?74LS32 or 74LS32N has 12 input-output pins for a total of four OR gates. To use the 74LS32  Logic gate IC, just power it with the Vcc and ground pins. The typical operating voltage of the IC is +5V, but it can also be operated in +7V. The output voltage of the IC on the pin Y is equal to the operating voltage of the IC. As per the OR gate truth table, if either one or both of the gate inputs are high, the output will be high. The truth table of OR gate  is given below: ABY000101011111OR Gate Truth Table According to the truth table, when both the inputs are low, the output will be zero. When either one or both the input of the Gate is high, the output will be high. 74LS32 Internal Diagram74LS32 ApplicationsBasic Logic CircuitsEncoders and DecodersMultiplexers and De-multiplexersOscillator circuitsNetworking and Digital Systems 74LS32 PackageComponent Datasheet74LS32 DatasheetFAQWhat is 74ls32?The 74LS32 is a Dual Input OR Gate with Quad package. It contains four independent gates each of which performs the logic OR function. Each gate has two inputs that’s why it is named Quad 2-Input OR Gate,   Logic level gates like 74LS32  and flip-flops play a vital role in digital electronics.What is the difference between 74ls32 and 74ls32n?74LS32N and  74LS32 have the same performance and function, both are 2-input four-OR gates. 74LS32 omits the description of the package form of the device. The package form of 74LS32N is plastic dual in-line.What is the difference between 74hc32 and 74ls32?74HC32 is a COMS device74LS32 is a TTL deviceThey have different current levels, different speeds, and different stability performance.What is the output current of 74ls32?High level output current, IOH= -0.4ma. Low-level output current IOL=8ma.What does the OR Gate do?The OR gate is a digital logic gate that implements logical disjunction – it behaves according to the truth table to the right. A HIGH output (1) results if one or both the inputs to the gate are HIGH (1). If neither input is high, a LOW output (0) results.How many independent gates does 74LS32 have?FourWhat is 74LS32 called?Quad 2-Input OR GateHow many input output pins does 74LS32 have?12What is the typical operating voltage of the 74LS32 IC?+7V 

Ⅰ IntroductionA line following car designed with LM393 Voltage Comparator capable of tracking on a specific runway. The line following car mainly includes a solar power supply part and a tracking control part. The control circuit part mainly includes a battery, a switch, first and second light sensitive circuits, a DC motor, a comparison circuit, and a motor drive circuit.This blog test shows that the line following car controlled by the LM393 voltage comparator has the characteristics of high control accuracy, fast start and stop, etc., and solves the problems of the complicated control circuit structure of theline following car and the large deviation of the driving trajectory.CatalogⅠ IntroductionⅡ What is LM393？Ⅲ What is A Line Following Car？3.1 Solar Power Design3.2 Line Following DesignⅣ Circuit Design of Line Following CarⅤ TestⅥ ConclusionFAQOrdering & QuantityⅡ What is LM393？The LM393 offers exceptional value for cost-sensitive applications with a lower offset voltage, higher supply voltage capability, lower supply current, lower input bias current, shorter propagation delay, as well as improved 2 kV ESD performance and input robustness with dedicated ESD clamps.The LM393 devices consist of two independent voltage comparators that are designed to operate from a single power supply over a wide range of voltages. The quiescent current is independent of the supply voltage, and the outputs can be connected to other open-collector outputs to achieve a wired AND relationship.Figure 1. LM393Ⅲ What is A Line Following Car？A line following car is a car that can travel along a preset trajectory. In the process of driving the line following, how to make the car can accurately follow the trajectory without large deviations is the fundamental application of the line following car. However, the existing line following car generally uses the infrared reflection method to feed back the driving trajectory of the car, the control circuit structure is more complicated, and the infrared reflection is easily affected, so not only the cost is higher, but also the driving trajectory of the car is prone to deviation, so it often does not match the design trajectory.Using LM393 voltage comparator as the main control chip of the tracking car will be a better way. Use the resistance change of the photoresistor under the light intensity and the LM393 voltage comparator to control the left and right driving wheels of the car to realize the tracking drive of the car, and cooperate with the display circuit to understand the status of the car. The principle block diagram of line following car based on LM393 voltage comparator is shown in Figure 3.Figure 2. Line Following CarⅣ Circuit Design of Line Following CarThe circuit design of line following car based on LM393 voltage comparator mainly includes solar power supply and car tracking design.The main components of the line following car include a battery box, a control circuit board attached to the bottom of the battery box by double-sided adhesive, and several wheel assemblies installed on both sides of the control circuit board and a solar battery panel installed above the battery box .Figure 3. Block Diagram of Line Following Car3.1 Solar Power DesignThe line following car adopts battery power supply and storage. The solar battery board provides power for the battery, that is, the battery in the car is charged first, and only when the battery has enough power output voltage, the required voltage can be output at the output end of the battery to drive the tracing car.The design of the power supply part mentioned in this blog uses a single lithium battery charging management chip TP4057 with an input voltage of 4V 9V (typical value 5V), which can be used to change the resistance to control the charging current, and its adjustment range is 100mm 500mA and the cut-off voltage is 4.2V.The charging circuit has simple peripherals, no external switch tube is required, and has functions such as charging indication and full indication, anti-reverse battery positive and negative pole reverse connection protection, and power supply undervoltage protection. In addition to using solar panels to power the circuit, it can also work with USB power and adapter power.Figure 4. Schematic Diagram of Charging Circuit3.2 Line Following DesignThe car tracking adopts the LM393 voltage comparator as the control center of the entire tracking circuit. LM393 is a dual voltage comparator integrated circuit, which is composed of two independent precision voltage comparators. Its function is to compare two input voltages and change the level of the output voltage according to the level of the two input voltages. The schematic diagram using the LM393 voltage comparator as the tracking control circuit is shown in Figure 5.This car chooses red LED light as its light source. When the light source shines on white objects and black objects (the predetermined trajectory of the car is black), the reflectivity is different.The light is reflected onto the photoresistor through the ground. When the red LED light is projected on the white area and the black track line, the resistance of the photoresistor will be significantly different because of the different reflectance;By detecting the resistance change of the photoresistor, it can be judged whether the car is driving on the black track line.This car chooses red LED light as its light source. When the light source shines on white objects and black objects (the predetermined trajectory of the car is black), the reflectivity is different. The light is reflected onto the photoresistor through the ground. When the red LED light is projected on the white area and the black track line, the resistance of the photoresistor will be significantly different because of the different reflectance;By detecting the resistance change of the photoresistor, it can be judged whether the car is driving on the black track line.Figure 5. Schematic Diagram of TracingIf the resistance of the photoresistor changes, it means that the white area has been detected, and the car has deviated; at this time, the motor of the left or right wheel of the car is decelerated or even stopped to make the car return to the black track. The track car runs on a similar S-shaped route to achieve the line following function.When there is an imbalance (for example, one wheel is pressed on the black track line), the motor on one side is stopped immediately, and the motor on the other side is accelerated to rotate, so that the car can correct the direction and return to the correct direction. The whole process is a closed loop control, so you can quickly and sensitively control the movement of the line following car.At the same time, the photoresistor can detect the intensity of the external light. The stronger the external light is, the smaller the resistance value of the photoresistor is. The left and right wheel drive of this tracking car uses a DC motor with a reduction gear. The DC motor drives the car to slow down, otherwise the car will run too fast if the speed is too high.Moreover, the torque is too small to run even without deceleration. The motor used in this line following car has integrated a reduction gear to greatly reduce the difficulty of production and debugging. Compared with the use of a single-chip microcomputer as the control circuit, the control circuit composed of the LM393 voltage comparator has a simpler structure, is convenient for assembly and debugging, and has a lower cost.Ⅴ TestFirst of all, place the car on the white background test field of the black track line (the black runway is the car's preset track), and turn on the switches S1, S2, solar panels (or batteries) to provide electricity, so that the voltage comparator controls the start of two DC motors to drive the wheel assemblies on both sides of the car. Our DIY line following car began to drive along the designed track (black runway)!During the driving of the car, the light-emitting diodes D2 and D3 on the left and right sides of the car both emit red light sources. Because the light source irradiates the black runway and the white runway with different reflectivity, and the photoresistor can detect the external light intensity, the stronger the external light, the smaller the photoresistor resistance, the weaker the external light, the greater the resistance.Therefore, when the red LED light is projected onto the black and white runway, because of the different reflectance, the resistance of the photoresistor will be significantly different.Figure 6. Red LEDWhen the light source is reflected by the runway to the photoresistors R14 and R15, the comparator can determine whether the car is driving on the black track line or the white area according to the changes in the resistance of the photoresistors on both sides. And through the diodes and photoresistors on the left and right sides, we can also determine which side the car is deflecting at this time.When an imbalance occurs (for example, the side of the car is pressed against the white area), the DC motor on one side is immediately stopped, and the DC motor on the other side is accelerated to rotate, so that the car can correct the driving direction and return to the correct driving direction (black track on-line.Actually, we can see that the left and right driving wheels of the car rotate in turn and stop driving the car forward; there is a process of deviation, correction, deviation, and correction; but it always advances along the established black trajectory.Ⅵ ConclusionThe solar tracking car discussed in this blog:Passed the test and successfully realized the car's line following;Can be powered by solar energy or battery;Strong stability and anti-interference ability, high control accuracy, fast start and stop;Solved the problems of complicated control circuit of line following car and large deviation of driving trajectory.Using only the LM393 voltage comparator as the controller circuit allows us to assemble and debug conveniently and at a lower cost. The use of non-single chip control is a feature of this line following car.Figure 7. LM393In summary, the line following car based on LM393 control is suitable for technological innovation and technology promotion.FAQWhat is LM393 used for?The LM393 series are dual independent precision voltage comparators capable of single or split supply operation. These devices are designed to permit a common mode range−to−ground level with single supply operation. How does LM393 comparator work?The LM393 is a dual differential comparator; this means that it accepts 2 inputs for comparison. It compares these voltage inputs and determines which is the larger value. Based on this, electronic decisions can be made based on which input is greater and which is smaller. What is the control circuit part of the line following car?A DC motor What is the purpose of the LM393 devices?Wired AND relationship What is a line following car?A car that can travel along a preset trajectory  After reading the blog, have you better understand LM393?  Finally, if you have any questions about LM393, please do not hesitate to leave a message in the comment section below!

The PCF8574 is an I2C bus to 8-bot parallel bus IO expander IC. It provides GPIO  expansion for many microcontrollers in a simple and cost-effective method. The interface for this IC is I2C  (or I2C) using SDA  (Data) and SCL  (Clock) lines. So, if your microcontroller has a limited number of IO pins and has I2C capability, then you can use this IC to expand the IO pins.Here is a video of PCF8574 I2C GPIO Expander TutorialCatalogPCF8574 PinoutPCF8574 CircuitPCF8574 ApplicationPCF8574 FeaturePCF8574 AdvantagePCF8574 PackagePCF8574 ParametersPCF8574 ManufacturerPCF8574 DocumentsPCF8574 Functional Block DiagramComponent DatasheetFAQPCF8574 PinoutPINTYPEDESCRIPTIONNAMERGTRGYDGV or PWDW or NA [0..2]2, 3, 46, 7, 96, 7, 91, 2, 3IAddress inputs 0 through 2. Connect directly to VCC or ground. Pullup resistors are not needed.GND915158—GroundINT141113OInterrupt output. Connect to VCC through a pullup resistor.NC-3, 8, 13, 183, 8, 13, 18-—Do not connectP[0..7]5, 6, 7, 8, 10, 11, 12, 1310, 11, 12, 14, 16, 17, 19, 2010, 11, 12, 14, 16, 17, 19, 204, 5, 6, 7, 9, 10, 11, 12I/OP-port input/output. Push-pull design structure.SCL152214ISerial clock line. Connect to VCC through a pullup resistorSDA164415I/OSerial data line. Connect to VCC through a pullup resistor.VCC15516—Voltage supplyPCF8574 CircuitPCF8574 four-key four-LED control circuitPCF8574 Application1. Telecom Shelters: Filter Units2. Servers3. Routers (Telecom Switching Equipment)4. Personal Computers5. Personal Electronics6. Industrial Automation7. Products with GPIO -Limited ProcessorsPCF8574 Feature1. Low Standby-Current Consumption of 10 μA Max2. I2C to Parallel-Port Expander3. Open-Drain Interrupt Output4. Compatible with Most Microcontrollers5. Latched Outputs with High-Current Drive Capability for Directly Driving LEDs6. Latch-Up Performance Exceeds 100 mA Per JESD 78, Class IIPCF8574 AdvantagePCF8574 8-bit input/output (I/O) expanderThis 8-bit input/output (I/O) expander for the two-line bidirectional bus (I2C) is designed for 2.5-V to 6-V VCC operation.The PCF8574 device provides general-purpose remote I/O expansion for most microcontroller families by way of the I2C interface [serial clock (SCL), serial data (SDA)].The device features an 8-bit quasi-bidirectional I/O port (P0–P7), including latched outputs with high-current drive capability for directly driving LEDs. Each quasi-bidirectional I/O can be used as an input or output without the use of a data-direction control signal. At power-on, the I/Os are high. In this mode, only a current source to VCC is active.PCF8574 PackagePART NUMBERPACKAGE (PIN)BODY SIZE (NOM)PCF8574TVSOP (20)5.00 mm × 4.40 mmSOIC (16)10.30 mm × 7.50 mmPDIP (16)19.30 mm × 6.35 mmTSSOP (20)6.50 mm × 4.40 mmQFN (16)3.00 mm × 3.00 mmVQFN (20)4.50 mm × 3.50 mmPCF8574 ParametersNumber of I/Os8FeaturesInterrupt pinSupply voltage (Min) (V)2.5Supply voltage (Max) (V)6Addresses8RatingCatalogFrequency (Max) (kHz)100Operating temperature range (C)-40 to 85PCF8574 ManufacturerTexas Instruments Inc. (TI)  is an American technology company that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globally. Its headquarters are in Dallas, Texas, United States. TI is one of the top ten semiconductor companies worldwide, based on sales volume. Texas Instruments's focus is on developing analog chips and embedded processors, which accounts for more than 80% of their revenue. TI also produces TI digital light processing (DLP) technology and education technology products including calculators, microcontrollers and multi-core processors. To date, TI has more than 43,000 patents worldwide.PCF8574 DocumentsPCF8574 and PCF8574A Application ClipAug. 18, 2004Improving System Interrupt Management Using the PCF8574 and PCF8574A I/O Expande   Jul. 27, 2001PCF8574 Functional Block Diagram Simplified Block Diagram of Device Simplified Schematic Diagram of Each P-Port Input/OutputComponent DatasheetPCF8574 DatasheetFAQWhat is the interface for the PCF8574?SDA (Data) and SCL (Clock) linesWhat does the PCF8574 feature?8-bit quasi-bidirectional I/O portWhat type of expander is designed for the two-line bidirectional bus?8-bit input/output (I/O) expanderWhat is PCF8574A?The PCF8574 is a silicon CMOS circuit. It provides general purpose remote I/O expansion for most microcontroller families via the two-line bidirectional bus (I2C). The device consists of an 8-bit quasi-bidirectional port and an I2C-bus interface.What is I2C IO Expander?The I/O expander adds additional GPIO ports. These can be used as both inputs, and outputs at either 3.3V or 5V. ... I2C is a two wire bus, the connections are called SDA (Serial Data) and SCL (Serial Clock). 

In today's blog, I'll unlock the details of CR1220, the lithium coin battery. CR1220 is a battery cell, also known as a lithium coin battery that comes with a high voltage of around 3V and encompasses an ultra-compact design, helping you get rid of the difficulty of buying two or three extra traditional batteries, saving both the cost and the space needed to adjust these cells in the relevant devices.Game Boy Color - Cartridge Battery Mod - Game Save Battery Holder Hack - CR1220CatalogCR1220 General DescriptionCR1220 SpecificationsCR1220 EquivalentCR1220 FeaturesCR1220 ApplicationsCR1220 DimensionsComponent DatasheetFAQCR1220 General DescriptionCR1220 is a lithium coin battery that is mainly used in high-powered devices such as keyless input devices, glucose monitors, heart rate monitors, and toys & games. It comes in cylindrical shape and may retain power for a maximum period of time. If it is spared alone for one year, only 1% of the total battery capacity will be discharged. This battery is slightly different from CR2032 in terms of battery capacity, weight and lithium content, since it comes with a capacity of 35mAh with a weight of 0.8g and a lithium content of 0.006 grams, followed by a capacity of 285mAh, a weight of 3 grams and a lithium content of 0.109 grams. It is important to note that there is no need for coatings or other foreign objects on the surface of terminals that could have a serious impact on the actual use or performance of this coin cell. They can be designed using two methods: an extra mechanical tool, such as a screwdriver, is required to unlock the battery compartment, or two independent movements of the securing mechanism can be applied by a single hand. These battery compartments come with the ability to hold different cells where the capacity varies depending on the size.CR1220 SpecificationsClassificationLithium CoinChemical SystemLithium / Manganese Dioxide (Li/MnO2)DesignationANSI-5012LC, IEC-CR1220Nominal Voltage3.0 VoltsTypical Capacity37 mAh (to 2.0 volts)(Rated at 45K ohms at 21°C)Typical Weight0.8 grams (0.03 oz.)Typical Volume0.25 cubic centimeters (0.02 cubic inch)Max Rev Charge1 microampereEnergy Density153 milliwatt hr/g, 464 milliwatt hr/ccTypical Li Content0.006 grams (0.0002 oz.)Operating Temp-30C to 70CSelf Discharge~1% / yearCR1220 EquivalentDL1220, ECR1220, BR1220, 280-208, DL1220B, BR1220-1W, CR1220-1W, KCR1220, LM1220, 5012LC, SB-T13, L04CR1220 FeaturesLightweight, High Voltage and High Energy DensityExcellent Discharge CharacteristicsExcellent Leakage ResistanceExcellent Long-Term ReliabilityUL Approved PartsCR1220 ApplicationsCR1220 comes with a wide range of applications requiring on-the-fly temporary power. Here are some major applications of this coin cell.Keyless entry devicesGlucose monitorsImplantable cardiac defibrillatorsHeart-rate monitorsArtificial cardiac pacemakersToys & gamesCR1220 DimensionsComponent DatasheetCR1220 Datasheet FAQWhat is the difference of cr1220 and cr1225? do they work the same or no?Dimensions are different and they cannot work the same.CR1220 12mm(Diameter)*2.0mm(Thickness), CR1225 12(Diameter)*2.5mm(Thickness)What are cr1220 batteries used for?The Energizer CR1220 battery is a long lasting, high performing CR1220 lithium button cell battery. CR1220 batteries are used in a variety of applications, including watches, organizers, calculators, computer and medical equipment.How long do cr1220 batteries last?10 years.Coin Lithium - CR1220. CR1220 batteries are used in a wide range of products like toys, fitness and medical appliances. These button cell lithium batteries have a shelflife of up to 10 years.Can I use CR2032 instead of CR1220?The number is the size of the battery: 2032 is 20mm diameter, 3.2mm thick. 1220 is 12mm diameter, 2mm thick. So one will not physically fit in place of the other.What is CR1220 used for?The Energizer CR1220 battery is a long lasting, high performing CR1220 lithium button cell battery. CR1220 batteries are used in a variety of applications, including watches, organizers, calculators, computer and medical equipment.What shape does CR1220 come in?CylindricalHow much of the battery capacity will be discharged if CR1220 is spared for one year?1% 

I DescriptionThis blog mainly introduces the use of the LM358 integrated operational amplifier. We also introduce how to use the LM385 chip to implement a voice-activated delay switch circuit. In addition, the blog also analyzes circuit composition, circuit analysis, and circuit production and debugging. This circuit we will discuss has the following advantages: small size, economical and practical, easy to make, and intuitive. Therefore, LM358 is especially suitable for beginners' circuit learning.CatalogI DescriptionII Introduction2.1 Voice-activated delay switch2.2 lm358III Circuit function and schematic diagramIV Circuit analysis4.1 Linear part4.2 Non-linear partV Circuit production and debuggingVI ConclusionComponent DatasheetFAQOrdering & QuantityII Introduction2.1 Voice-activated delay switchWhat is a voice-activated delay switch? The voice-activated delay switch is mainly used in the corridor of a residential area or office. The function of this switch is that only after dark when someone walks through the stairway and makes footsteps or other sounds, the corridor lights will automatically light up to provide illumination. When people enter the house or walk out of the apartment, the corridor lights will automatically turn off after a delay of 30 seconds to achieve the purpose of energy-saving.The working principle of the LM358-based circuit introduced in this blog is simple and easy to understand, suitable for beginners' circuit production.2.2 LM358LM358 is a dual operational amplifier. There are two independent operational amplifiers with high gain and internal frequency compensation inside, which are suitable for a single power supply with a wide range of power supply voltage, and also suitable for dual power supply operation mode. In addition, under the recommended operating conditions, the power supply current is independent of the power supply voltage. The scope of application of LM358 includes sensor amplifiers, DC gain modules, and all other occasions where operational amplifiers can be powered by a single power supply.The features of LM358 are as follows:Internally Frequency Compensated for Unity GainLarge DC Voltage Gain: 100 dB Wide Bandwidth (Unity Gain): 1 MHz (Temperature Compensated)Wide Power Supply Range:– Single Supply: 3V to 32V– Or Dual Supplies: ±1.5V to ±16VVery Low Supply Current Drain (500 μA)—Essentially Independent of Supply VoltageLow Input Offset Voltage: 2 mVInput Common-Mode Voltage Range Includes GroundDifferential Input Voltage Range Equal to the Power Supply VoltageLarge Output Voltage SwingUnique Characteristics:– In the Linear Mode the Input Common-Mode Voltage Range Includes Ground and the Output Voltage Can Also Swing to Ground, even though Operated from Only a Single Power Supply Voltage. – The Unity Gain Cross Frequency is Temperature Compensated.– The Input Bias Current is also Temperature Compensated.III Circuit function and schematic diagramThe LM358-based circuit uses an integrated operational amplifier, and the basic circuit in terms of linearity and nonlinearity is used to make a voice-activated delay switch. The circuit is shown in Figure 1. Figure 1. LM358 sound control delay switch circuit diagramThis circuit uses electret microphones to collect sound signals. First of all, amplify the signal with an inverted proportional amplifier circuit composed of an integrated operational amplifier LM358. Subsequently, the voltage comparator composed of LM358 is used to control the relay to turn on.IV Circuit analysis4.1 Linear partThe linear part of the circuit shown is the sound amplifier circuit, which is composed of an electret microphone and an inverted proportional amplifier circuit,  The inverse proportional amplifying circuit in this circuit is implemented by LM358. LM358 contains two independent, high-gain dual operational amplifiers, suitable for a single power supply with a wide range of power supply voltage. At the same time, it is also suitable for dual power supply mode.The electret microphone in this circuit converts sound waves into electrical signals, and the inverted proportional amplifier circuit amplifies the electrical signals and provides them to the subsequent circuits. The two capacitors C1 and C2 are coupling capacitors. The signal amplification factor of this circuit is:4.2 Non-linear partThe non-linear part is a voltage-controlled delay switch circuit. The sound signal collected by the electret microphone is amplified by an inverted proportional amplifier circuit and then coupled via C2 to turn on the diode VD1 and charge the capacitor C3.When the charging voltage rises to Uth=[R7/(R5+R7)]VCC, the voltage comparator outputs a high level, and the transistor is saturated and turned on. At this time, the relay coil is energized, the switch K is closed, and the light-emitting diode is on.There is no sound from outside at this time. The diode VD1 is turned off, and the capacitor C3 discharges to R6. When the discharge voltage drops to Uth, the voltage comparator outputs a low level, and the transistor is cut off. At this time, the relay coil is powered off, the switch K is off, and the light-emitting diode is off.V Circuit production and debuggingFirst, list the components according to the schematic diagram, and then check each component. We need to make sure everything is correct before we start welding the circuit. It is shown in Figure 2 after completion. Figure 2. Physical picture of LM358 circuitFinally, connect the 9V DC power supply to debug the circuit. When sound is emitted to the electret microphone, the corresponding three diodes will light up. After a period of delay, the light will go out. Then adjust the resistance of the variable resistor and the corresponding delay time changes happened.VI ConclusionThe voice-activated delay switch circuit described in this article is designed based on LM358 components. Beginners can further deepen the application of the LM358 integrated operational amplifier through the study of this circuit, and can better grasp the welding technology of the circuit and the troubleshooting method of the circuit fault.Component Datasheet LM358 DatasheetFAQWhat is lm358 op amp?LM358 is a dual op-amp IC integrated with two op-amps powered by a common power supply. It can be considered as one half of LM324 Quad op-amp which contains four op-amps with common power supply. The differential input voltage range can be equal to that of power supply voltage.What is lm358 used for?LM358 can be used as transducer amplifier, DC gain block etc. It has large dc voltage gain of 100dB. This IC can be operated on wide range of power supply from 3V to 32V for single power supply or from ±1.5V to ±16V for dual power supply and it also support large output voltage swing.Why lm358 is used in IR sensor?IC Lm358 is used as a comparator when IR receiver senses IR radiations. When the o/p of lm358 goes high, then LED connected at the o/p turns ON. The output pin of the IC LM358 is used to interface with PIC microcontroller.How does an lm358 work?IC LM358– LM358 consists of two independent, high gain operational amplifiers in one package. Important feature of this IC is that we do not require independent power supply for working of each comparator for wide range of power supply. LM358 can be used as transducer amplifier, DC gain block etc.What is the difference between lm358n and lm358p?The suffix denotes the manufacturer's packaging code. The 'N' is used by most manufacturers for the plastic 8-pin package. The 'P' is used by a few manufacturers for the plastic 8-pin package. Raven Luni is right, there is NO difference between the two devices, just the mfgrs.How do I know if my lm358 op amp is broken?Measure the DC voltage at the +input. then measure the DC voltage at the output. if the results are significantly different, the opamp is most likely shot. if they are the same, the opamp is most likely ok and the problem is something else.What is the difference between lm386 and lm358？The LM386 is a complete audio power amplifier, the LM358 is a dual operational amplifier. When using the LM358 e.g. as a pre-amplifier, you will have to supply a separate power amplifier.What is a dual op amp?With a dual supply op amp, the V+ terminal of the op receives a positive voltage and the V- terminal connects to negative voltage. Therefore, any input signal fed into the op amp can swing from the positive voltage supply to the negative voltage supply.What is LM series?The following is a list of LM-series integrated circuits. ... The LM series originated with integrated circuits made by National Semiconductor. The prefix LM stands for linear monolithic, referring to the analog components integrated onto a single piece of silicon.How to import lm358 into LTspice?1. Download model file and unzip.2. Place .cir file in same folder as schematic.3. Place "opamp2" symbol on schematic.4. Change "opamp2" value to LMX58_LM2904.5. Place directive on schematic ". lib LMx58_LM2904. CIR" without quotes. 

I DescriptionThis blog mainly discusses and solves the following problem: How to use an LM339 voltage comparator to make a reservoir water level gauge?According to water level, this design performs signal processing and controls the potential of multiple voltage comparators, so the output will change accordingly. Therefore, under its drive, LED can not only emit light but also achieve the effect of indicating the water level.Figure 1. LM339CatalogI DescriptionII IntroductionIII Woking PrincipleIV Device selection and Component Production4.1 device selection4.2 Part ProductionV Installation and Debugging5.1 Detection Part5.2 Display PartVI ConclusionFAQOrdering & QuantityII IntroductionDue to insufficient water supply in some residential areas, pump workers must first store water in the reservoir and then supply water in a regular manner. In this way, the pump worker must know the water level of the reservoir at any time in the pump room.In the past, electrodes such as copper rods or stainless steel were used to detect the water level of the pool. However, due to electric corrosion, the function of the electrode is lost soon after use. For this reason, this blog uses an LM339 voltage comparator to make water level gauge,  This not only eliminates the pain of often changing electrodes but also simple and easy. How simple is it? Only two wires need to be connected from the reservoir to the pump room. After more than two years of operation, its performance has been stable and reliable, achieving the expected results.III Woking PrincipleThe main circuit of the water level gauge is composed of 4 LM339  voltage comparators,  This kind of integrated circuit has the characteristics of easy purchase, low price, single power supply operation, and wide differential range.Each LM339  has 4 independent voltage comparators  (15 in this design). As long as the potential difference between the positive and negative input terminals is 10mV, the output terminal can be reliably switched from one state to another.When the positive input terminal is 10mV higher than the negative input terminal, its output terminal is high;When the negative input is 10mV higher than the positive input, its output is low. In addition, LEDs can be driven directly.Then how to make the output end of LM339  have high and low-level changes? In specific use, an appropriate resistance is generally added between the output terminal and the positive power supply. This resistor is called a pull-up resistor. That is, when the output terminal of LM339  is in a high impedance state, the potential of the output terminal is pulled up by the resistor.Figure 2. Block Diagram of Water Level GaugeThe principle block diagram of the device is shown in Figure 2.The voltage signal measurement consists of a reed switch and a voltage divider resistor. The ring magnets suspended in the water are in different positions. Due to the principle of electromagnetic induction, not only the corresponding dry reed switch normally open contacts are closed, but also the corresponding voltage divider resistor is connected. Therefore, the circuit will pick up different voltage signals.The potential of the negative input terminal of the comparator is formed by a fixed voltage divider resistor. The measured voltage signal is compared with the set potential. The result of this is that the LED displays the water level when driven. In addition, an alarm is issued when the highest water level is reached to remind the pumper to stop water injection to prevent water overflow.The concrete circuit is shown as in Fig. 3.Figure 3. Water Level Gauge Circuit DiagramIn Figure 3, the power supply is + 12 V, and the depth of the pool is divided into 15 segments for display.In this picture:A1～A15 are voltage comparators  composed of LM339  ;GK1～GK15 are dry reed switches, the normally open contact is closed when the ring magnet is close to a certain dry reed switch;The voltage divider circuit composed of resistors R 1 to R 15 determines the potential of the positive input terminal of each comparator. The voltage of the positive input terminal of LM339  changes due to the different positions of the magnetic steel.The voltage divider circuit composed of resistors R 01 ~ R 030 determines the potential of the negative input terminal of each comparator. The potential of each negative input terminal is fixed after the determination.When the magnetic steel floating on the water surface is close to a certain dry reed switch, due to the partial pressure of R 1, R 2,…, R 15, the positive input terminals of the comparators A1, A2, …, A15 have different inputs. After this signal is compared with the potential set at the negative input of the comparator, there will be a corresponding output.From Figure 3, when GK1 pulls in, it is equivalent to holding the magnetic steel float at the upper limit water level. The positive input of each comparator is equal to the ground potential, which is lower than their negative input. Therefore, the output terminals are all low level, so all LEDs are lit. At this time, the output of A1 drops from high level to low level, and NE555 is triggered through capacitor C.NE555 is connected as a monostable circuit. Once triggered, its 3 pin will output a high level, which will drive the buzzer to alarm. Its duration is determined by the RC components connected to the 6 and 7 pins. When GK2 is closed, LED 2 ~ LED 15 should be on, and LED 1 should be off. At this time, the potential of the positive input terminal of each comparator is higher than the potential of the negative input terminal of A1 and lower than the potential of the negative input terminal of A2～A15, and so on.IV Device selection and Component Production4. 1 device selectiona. Set the negative input potential of each comparator to V sh.The negative input potential of each comparator is set artificially according to the number of segments divided into the power supply and water depth. Because the pool depth has been divided into 15 segments for display, starting from 2.0 V, the difference between each adjacent negative input terminal is 0.4 V. As shown in the first row in Table 1.b. Select the resistance between the negative input terminal of each comparator and the power supply, that is, the voltage divider resistance R 01 = R 03 =… = R 029 = 20 kΨ, set to R.c. Calculate the ground resistance R 02, R 04,..., R 030, which is R r.Suppose the resistance of the negative input terminal to the ground is R r, and the potential of each negative input terminal is V sh, according to circuit diagram 3:(1)From this formula:(2)For example, to make the potential of the negative input terminal of the voltage comparator A1 V sh = 2 V, according to equation (2), we can getAs shown in the second row and the first column in Table 1. The selection of the other resistors R 04, R 06,…, R 030 can be calculated according to the above formula (the result is a theoretical value, see the data shown in the second row in Table 1 for details).d. Determine the nominal resistance R b from R r. In fact, the nominal value of commercially available resistors is different from this calculated value. In specific applications, a nominal resistance R b with a similar resistance value can be selected. The specific value is shown in the third row of Table 1.e. Determine the potential V of the negative input terminal of each comparator A by R b. When the nominal value of resistance R b is selected, use the following formula to check the potential V generated by this resistance.(3)The specific potential value is shown in the 4th row of Table 1, compared with the set value in the 1st row, as long as it does not exceed ±0.1V.f. Determine the resistances R 1, R 2,…, R 15 of the positive input terminals of each comparator and set them as R zh.First find R 1, set the positive input potential of each comparator as V zh, when GK1 pulls in, it can be seen from Table 1 that 2V <V zh <2. 4 V, set V zh = 2. 2 V, R = 20 kΨ, according to formula (3), it can be listedThe solution is that R zh = R 1 ≈ 4.5 kΨ. This resistance is not the nominal value. Choose a similar nominal value of 4.8 kΨ. Then find the other resistances R 2, R3, …, R 15, which can all be calculated by this method. The result is the theoretical value, which has a slight deviation in practice. After correction, the value is shown in the fifth row of Table 1.After the above parameters are selected in this way, it can be ensured that when the water level in the pool reaches the lowest limit and the float holding the magnetic steel sinks to the lowest position, the magnetic steel separates from all the reed switches and the LEDs are all extinguished; And when the first reed switch GK1 is closed (equivalent to the water level in the pool reaches the highest limit, the float holding the magnetic steel rises to the highest position) LEDs are all on. When the float is at a certain position in the middle, the corresponding LED and the LEDs below are all on, and the LED above it is off, to show the water level. After the above calculation, the specific data shown in Table 1 is obtained.4.2 Part ProductionIt is necessary to measure the height from the lowest water level of the reservoir to the limit water level, and divide this height into 15 segments. The distance of each segment is less than 200mm, this distance can ensure that the magnetic steel can always attract an adjacent dry reed switch, so as to avoid display breakpoints. That is to prevent the magnetic steel from not attracting the upper dry reed pipe or the lower dry reed pipe during operation, so that the LED display is all extinguished, causing the illusion of waterlessness.For the connections of GK1, R1～GK15, R15, first solder them to a small printed circuit board with a width less than or equal to 20mm, and then use wires to connect them at a distance of less than or equal to 200mm, and encapsulate them in a 25mm hard plastic tube. . The upper and lower mouths of the pipe should be tightly sealed to prevent water leakage.The tube is covered with a ring-shaped magnet. After dropping a non-ferromagnetic heavy object on the lower end of the hard plastic pipe, the plastic pipe is vertically sunk into the bottom of the reservoir.A ring float is placed under the magnetic steel and is sleeved on the tube, and the upper end of the tube is fixed on the observation port above the reservoir. Due to the function of the float, the magnetic steel is always suspended on the water surface, rising and falling with the water surface. Note that the plane of the magnetic steel should always be parallel to the water surface, and the plastic pipe should be vertical to the water surface to prevent the magnetic steel from being stuck by friction with the pipe wall when the water level rises and falls.V Installation and DebuggingThe whole device consists of two parts:It is a detection part composed of a reed switch and various voltage dividers;It is the signal processing display part composed of LM339.5.1 Detection PartBefore encapsulating the plastic tube, put some silica gel in the tube to absorb the moisture in the tube and prevent the line in the tube from getting damp.If ring-shaped magnetic steel is used as the detection element, the reed pipe connected in series in the plastic tube should be realized by two staggered reed pipes.According to the electromagnetic induction theory, the analysis of the magnetic field lines of the magnetic steel shows that there are a small section of magnetic field lines parallel to the plane of the magnetic steel at the upper and lower openings of the magnetic steel.When this section is close to the reed switch, the direction of its magnetic field line is perpendicular to the direction of the reed of the reed switch. At this time, although the reed switch is very close to the magnetic steel, the contact is still released and disconnected, which will make all the LEDs go out. If two staggered reed pipes are used instead, the problem can be solved, and the staggered distance can be determined in experiments.5.2 Display PartThe water level of each segment is displayed by green Υ10 LED, and the limit water level is displayed by eye-catching red LED. If the LEDs are arranged neatly together, the water level in the pool can be clearly seen according to the on or off of the LEDs. Equipped with a buzzer, it will give the pump worker a clearer reminder.Note: From the detector in the pool to the circuit board of the pump room, it is best to use shielded wire to prevent interference signals from entering. We should also note that the power supply must be regulated.Fugure 4. lm339VI ConclusionThe negative input potential of the voltage comparator A1～A15 composed of  LM339  should be set according to a certain rule, and the potential interval between each other depends on the depth of the cell. If the water level is deeper, the interval can be smaller, and the number of sections can be selected more.The potential difference between adjacent comparators is generally 0.4V. If the potential difference is large, the selection of the resistance is easy; if the potential difference is small, because the nominal value interval of the general resistance is large, it is necessary to use an adjustable resistor to adjust the potential. Of course, in the case of small intervals, the smallest potential difference between each other should be greater than 10mV, otherwise, the input characteristics of  LM339 will not be able to distinguish the potential between each other.In addition, the voltage of the power supply and the nominal value of each resistance must be considered. This method can also be applied to other fields. Such as monitoring the water depth of rivers, rivers, lakes, and bays, the oil level of gas stations, and the depth of water tanks in water plants.FAQWhat is LM339?LM339 is a voltage comparator IC from LMx39x series and is manufactured by many industries. The devices consist of four independent voltage comparators that are designed to operate from a single power supply.What is the difference between LM324 and LM339?The LM324 has a complementary output while the LM339 is open collector. In the complementary output, current can flow in either direction as required (either source or sink) while the open collector output can only sink current.How does LM339 comparator work?The LM339 is a quad op amp comparator. A comparator works by a simple concept. Each op amp of a comparator has 2 inputs, a inverting input and a noninverting input. If the inverting input voltage is greater than the noninverting input, then the output is drawn to ground.What is comparator ic?A comparator is an electronic circuit, which compares the two inputs that are applied to it and produces an output. The output value of the comparator indicates which of the inputs is greater or lesser. Please note that comparator falls under non-linear applications of ICs.What is the replacement for LM339?LM311, LM324, LM397, LM139, LM239, LM2901What is a comparator circuit?A comparator circuit compares two voltages and outputs either a 1 (the voltage at the plus side; VDD in the illustration) or a 0 (the voltage at the negative side) to indicate which is larger. Comparators are often used, for example, to check whether an input has reached some predetermined value.What is the use of LM339?LM339 is used in applications where a comparison between two voltage signals is required. In addition with four of those comparators on board the device can compare four pairs of voltage signals at a time which comes in handy in some applications.