The Kynix Blog

 Overview of flicker noiseFlicker noise in oscillatorsFlicker Noise in SemiconductorFlicker Noise in op AmpHow to eliminate the flicker noise in op AmpThe working mechanism of flicker noiseEquation of flicker noiseThermal Noise vs. Flicker NoisePros of the flicker noiseCons of flicker noiseApplications of flicker noiseFlicker Noise FAQ Overview of flicker noiseElectronic noise known as flicker noise or 1/f noise happens naturally in almost all electronic parts. It can also result from contaminants in conductive channels, creation and recombination noise inside transistors due to base current, and other factors. Pink noise or 1/f noise are common names for this noise. All electrical devices commonly experience this noise, which has a variety of origins but is typically correlated with direct current flow. It is important in a variety of electronic fields and is important for oscillators used as RF sources.Because the power spectral density of this noise increases with frequency, it is sometimes referred to as low-frequency noise. Below a few KHz, this noise is generally visible. The flicker noise bandwidth ranges from 10 MHz to 10 Hz.Figure 1: The relationship between noise voltage and frequency Flicker noise in oscillatorsFlicker noise is inversely proportional to frequency, or 1/f, and in many applications, such as RF oscillators, there are parts where flicker noise, or 1/f noise, dominates, and other regions where white noise from sources like shot noise and thermal noise, or both, dominate. Within the oscillator the flicker noise expresses itself as sidebands that are near to the carrier, the other kinds of noise stretching away from the carrier with a smoother spectrum, however fading the larger the offset from the carrier.As a result, there is a corner frequency, fc, between the regions where the various types of noise predominate. It is typically discovered that the noise outside of the region where flicker noise predominates is phase noise for a system like an oscillator. As the offset from the carrier increases, this decays until flat white noise takes over.MOSFETs have a greater fc (which can reach GHz levels) than JFETs or bipolar transistors, whose fc is typically below 2 kHz. When building RF oscillators, flicker noise, or 1/f noise, is a crucial type of noise. Although it is frequently disregarded, its influence can be reduced by selecting the right gadget.Figure 2: Flicker noise in ocillators Flicker Noise in SemiconductorThe nature of semiconductor noise and how it is specified in semiconductor devices are covered in the section that follows. Since the origin of each semiconductor noise source is a random process, the noise's instantaneous amplitude is unpredictable. The distribution of the amplitude is Gaussian (normal).Figure 3: Flicker Noise in SemiconductorRemember that the RMS value of noise (Vn) equals the standard deviation (σ) of the noise distribution. A random noise source's RMS and peak voltages have the following relationship: VnP-P = 6.6 VnRMS. The crest factor of any signal is the ratio of peak-to-peak to RMS voltage (VnP-P/VnRMS). Because a Gaussian noise source statistically delivers peak-to-peak voltages that are 6.6 times the RMS voltage or higher 0.10% of the time, the crest factor in Equation 1 is 6.6. The likelihood of surpassing 3.3s is 0.001 in this shaded area under the noise voltage density curve in Figure 2. It's crucial to keep in mind that while random signals (like noise) multiply geometrically in a root sum square (RSS) way, associated signals add linearly. Flicker Noise in op AmpSince flicker noise occurs in addition to the thermal noise present in carbon composition resistors, it is frequently referred to as excess noise there. In varied degrees, other resistor types also show flicker noise, with wire coiled having the least. The type of resistor used will not impact the noise in the circuit because flicker noise is proportional to the DC current in the device, thus if the current is kept low enough, thermal noise will predominate. Scaling up resistors to minimize power consumption in an op amp circuit may result in a reduction in 1/f noise at the expense of an increase in thermal noise. Below is the formula to calculate the flicker noise:Figure 4: Flick noise formulaWhere Ke and Ki are proportionality constants (volts or amps) representing En and In at 1 Hz. fMAX and fMIN are the minimum and maximum frequencies in hertz. How to eliminate the flicker noise in op AmpWhat is the best way to deal with this loud, low-frequency noise? With the limited bandwidth, it is almost impossible to try and filter out this noise without changing the important signal. There is yet some hope, though. Although an amplifier's inherent 1/f noise is beyond the control of a system designer, this noise source can be reduced by choosing the right amplifier for the job. The best option is a zero-drift amplifier if 1/f noise is a major problem. Figure 5: zero-drift op amp chartAny amplifier that uses a constantly self-correcting architecture is referred to as "zero-drift" in the industry, regardless of whether it uses an auto-zero topology, a chopper-stabilized topology, or a combination of the two. No matter the specific architecture used, the objective of zero-drift amplifiers is to reduce offset and offset drift. Other dc features, such common-mode and power supply rejection, are also significantly enhanced during the procedure. The fact that the 1/f noise is eliminated during the offset correction procedure is another significant advantage of these self-correcting designs. This noise source occurs at the input and is relatively slow moving, hence it looks to be a component of the amplifiers offset and gets adjusted accordingly.  The working mechanism of flicker noiseBy raising the overall noise level above the thermal noise level, which exists in all resistors, flicker noise is produced. In contrast, wire-wound resistors have the least amount of flicker noise. This noise is merely present in thick-film and carbon-composition resistors, where it is referred to as surplus noise. Charge carriers that are sporadically trapped and released between the interfaces of two materials may be the source of this noise. Because instrumentation amplifiers use semiconductors to record electrical signals, this phenomena is common in those materials.This noise is merely inversely proportional to the frequency. There are various areas in many applications, such as RF oscillators, where noise predominates, and other areas where white noise from sources like shot noise & thermal noise predominates. A correctly constructed system is typically dominated by this low-frequency noise. Equation of flicker noiseSimply put, nearly all electronic components produce flicker noise. In light of this, the noise is discussed in respect to semiconductor devices, notably MOSFET devices. The formula for this noise is S(f) = K/f. Thermal Noise vs. Flicker NoiseThermal NoiseFlicker NoiseIn order to use SAR data both quantitatively and qualitatively, thermal noise must be eliminated by normalizing the backscatter signal throughout the whole SAR image.Several methods, like ac excitation and chopping, can be used to reduce this noise.The lower parasitic resistance components will result in a reduction in the intensity of thermal noise.Wherever the offset voltage of the amplifier is reduced, this noise intensity will be reduced using a chopper or chopper stabilization approach.Anytime current passes through a resistor, thermal noise results.Semiconductors used in instrumentation amplifiers to record various electrical signals typically experience this noise.Johnson noise, Nyquist noise, and Johnson-Nyquist noise are further names for this sound.1/f noise is another name for this noise.Thermal noise is the noise caused by the equilibrium thermal agitation of the electrons in an electrical conductor.Flicker noise is the sound produced by randomly trapped and released charge carriers at the interfaces of two materials. Pros of the flicker noiseAs the noise is low frequency, it will become quieter if the frequency increases.It is an innate noise present in semiconductor devices that is caused by their physics and manufacturing process.The effects are typically seen in electrical components at low frequencies. Cons of flicker noisePerformance can be hampered by this noise in any precision DC signal chain.In all varieties of resistors, the overall noise level can be raised above the thermal noise level.It is frequency dependant. Applications of flicker noiseCertain passive devices and all active electronic components contain this noise.This phenomena typically happens in semiconductors, which are primarily used to store electrical signals in instrumentation amplifiers.The amplifying capabilities of the device are limited by this noise in BJTs.In resistors made of carbon, this noise is present.This noise typically appears in active gadgets because the charge conveys unpredictable behavior. Flicker Noise FAQFlicker noise is measured in what ways?Similar to other types of noise measurement, flicker noise in current or voltage can be measured. The sampling spectrum analyzer instrument extracts a discrete sample from the noise and uses the FFT method to produce the Fourier transform. Low frequencies are beyond the capability of these sensors to accurately measure this noise. Thus, sampling equipment is wideband and has a high noise level. They can reduce the noise by averaging many sample traces. Due to its narrow-band acquisition, conventional-type spectrum analyzer equipment nonetheless have a higher SNR. What should I do to stop the flickering noise?By a chopper stabilization technique that lowers the amplifier's offset voltage, this noise can be effectively eliminated. Flicker Noise: Why Is It Pink?Pink noise, which has a spectral power density reduction of 3 dB per octave, is also known as flicker noise. As a result, the frequency has an inverse relationship with the pink noise band power. Lower power is produced at higher frequencies. Why is flickering called pink noise?One of the most frequently seen signals in biological systems is pink noise. The term originates from the pink appearance of visible light with this power range. White noise, on the other hand, has an equal strength throughout all frequency ranges. How is flicker noise measured?Flicker noise is proportional to the inverse of the frequency, i.e. 1/f and in many applications such as within RF oscillators there are sections in which the flicker noise, 1/f noise dominates and other regions where the white noise from sources such as shot noise and thermal noise dominate.

Overview: The development of lithium-ion batteries as a whole is greatly influenced by their charging systems. The charging technologies, the configuration of the overall charging system, and the charging sequence of electric vehicles are discussed in this article. Evolution of Electric Vehicles The use of electric and hybrid electric vehicles (EVs/HEVs) has grown significantly in recent years, resulting in reduced dependence on fossil fuels and greenhouse gas emissions. This has prompted a wide range of scientific sectors to work on EV/HEV technologies in an effort to replace high-polluting combustion engines. Most research on batteries has been focused on two things: making new chemical compounds to make high-performance batteries and recycling old batteries to avoid big problems with disposal and bad effects on the environment. In engineering equipment, batteries are a frequent source of energy storage. There are many different types of rechargeable batteries with different chemical structures, such as lead acid, nickel cadmium, lithium-ion, etc. These batteries can be chosen based on the design requirements of a storage system, such as capacity, voltage, life, and weight. Rechargeable lithium-ion batteries are used in EVs and HEVs because they have the most power, the highest energy density, and the longest life cycles. This is especially important in light-duty vehicles, where weight is important.  Charging Technologies of Lithium-ion Batteries Lithium-ion batteries are charged optimally with the aid of a battery charger. EV battery chargers are classified as on-board and off-board types based on how fast and how long it takes to charge, as well as when the process starts and ends. On-board chargers are made up of an AC-DC converter for adjusting the voltage and correcting the power factor and a DC-DC converter for regulating the current going into the battery. Because of their size and cost, these chargers only have power levels 1 and 2. Off-board chargers are used to get a high power rate and shorten the time it takes to charge. Fast charging stations use these types of chargers. They have level 3 power and are usually found in public places. A fast charger station is a three-phase grid-connected AC-DC converter. Based on the transformer position for galvanic isolation, there are two common topologies, as shown in Fig. 1. One traditional solution is a big transformer with a line frequency, which makes the charger heavier and less powerful. To solve these problems, a power electronics-based solution is used that uses an isolated DC–DC converter made up of a high-frequency isolated transformer. Most have an active front end (AFE) rectifier that can correct the power factor and an isolated DC-DC converter. A full-bridge DC-DC converter is used to get high power density, efficiency, and reliability. Fig. 1. Fast charger station topologies. Source: IET Power Electronics Most EV control schemes used in fast charge stations are based on the topology of the converter and don't take the chemical structure of the battery into account. But some studies show that charging methods based on electrochemical technologies are more efficient than traditional methods. The constant current–constant voltage (CC–CV) method is one of the most common ways to charge. In CC mode, the battery is charged with a constant current until a certain voltage is reached, at which point the mode changes to CV and stays there until the charge is done. The current drops to a certain value at the end. This method is used most of the time because it is easy to use and cheap. But its performance depends upon the magnitude of the charge current, the time it takes to switch from CC to CV, and the rise in temperature. A high-efficiency charging method that works well can be achieved if these values are properly chosen. System Configuration The power stage and the control unit make up the charger system, as shown in Fig. 2. The power stage has a three-phase AFE rectifier, a full-bridge DC-DC converter, a low-pass filter, and a battery. The control unit has a detect phase unit, an FDA, a current controller, and a modulator unit. A full bridge DC-DC converter is reliable and can control many things at once. This converter is used to charge batteries. It has an H-bridge inverter, a high-frequency transformer, and full-bridge diodes.  Fig. 2. Overall charge system configuration. Source: IET Power Electronics The switching method of a DC-DC converter is based on phase-shifting pulse width modulation. The amplitude of the output voltage is changed by changing the angle between the complementary pulses of the switches. The control unit is made up of four smaller parts: phase difference detection, frequency detection algorithm (FDA), controller, and modulator. By injecting a sinusoidal ripple current with a specific frequency, the phase difference between the current and voltage can be found. Then, the perturb and observe (P and O) algorithm is used to find the FDA unit's optimal frequency, which has the least phase difference. The next step is for the current control unit to make a control signal, which is the duty cycle of the DC-DC converter. In the last step, the modulator uses the control signal to make the right switching pulse. Sinusoidal Ripple Charging Scheme (SRC) A separator and two electrodes make up a Li-ion rechargeable battery, as indicated by the electrochemical model in Fig. 3. Li+ ions are transferred from the cathode to the anode during the charging process. Conventional battery charging schemes, like CV and CC-CV, have problems, such as taking a long time to charge. In the SRC method, an AC current with a DC offset current is used to charge the battery.  Fig. 3. Lithium-ion battery charging process. Source: IET Power Electronics Accordingly, it can cut down on the time it takes to charge a battery by figuring out the optimal ripple current frequency and making sure that the battery's ac impedance is as low as possible. The battery's dynamic model's impedance spectrum backs up this assumption. Compared to the SRC charging method, the square pulse charging method, which is a type of AC ripple current charging, is less efficient, causes the temperature to rise faster, and takes longer to charge.  Summarizing with Key Points: Some of the takeaways from the article are as follows: Rechargeable lithium-ion batteries are used in electric and hybrid electric vehicles because of their high power, high energy density, and prolonged life cycles.Electric vehicle battery chargers are categorized as on-board and off-board, depending on how quickly and how long it takes to charge a battery, as well as when the process begins and ends.On-board chargers only have up to 1 and 2 power levels and are composed of an AC-DC converter and a DC-DC converter. An off-board charger that has a three phase grid-connected AC-DC converter is the fast charging station. They are typically installed in public areas and have level 3 power.An isolated DC–DC converter constructed of an isolated high-frequency transformer solves these concerns with traditional chargers. Full-bridge DC-DC converters provide excellent power density, efficiency, and reliability.The CC–CV charging method is popular because it's cheap and straightforward to use. However, its performance depends on the charge current, time to switch from CC to CV, and temperature rise. The power stage and the control unit make up the charger system. The power stage has a three-phase AFE rectifier, a full-bridge DC-DC converter, a low-pass filter, and a battery. The control unit has a detect phase unit, an FDA, a current controller, and a modulator unit.The control unit has four smaller parts: phase difference detection, frequency detection algorithm, controller, and modulator. The phase difference between the current and voltage can be found by injecting a sinusoidal ripple current with a certain frequency. This blog post is part of a full research article from IET Power Electronics. The featured image is used courtesy of OPEN AI.

Overview: The availability of charging infrastructure is the most critical factor in the market penetration of commercial electric vehicles. In this article, a concise evaluation of a variety of topics related to the development of such infrastructure is provided.Charging InfrastructureThe SAE J1772 standard categorizes the electric vehicle (EV) charging infrastructure into three levels based on the charging power rate, voltage, current, and installation location, as shown in Table 1. Levels 1 and 2 are known as slow chargers, while level 3 is a fast charger. These levels indicate how long EVs take to charge.Table 1. Charging Levels of EV According to the SAE J1772 Standard. Source: IEEE Accessi The standard of North America.ii Typical values of DC charging station.iii Developed DC charging station. By the end of 2018, there were roughly 5.2 million light-duty vehicles (electric truck) charging stations installed worldwide. While public charging stations reached 1,44,000 fast chargers and 3,95,000 slow chargers, the majority of these stations were installed as slow-charging private stations. Numerous plans to accelerate the deployment of charging infrastructure were also announced. The majority of these announcements concerned chargers from the private sector with various capacities. Other announcements deal with publicly accessible chargers and make fewer promises for infrastructure for charging on highways. The power needs of these vehicles determine whether the current charging infrastructure is appropriate for commercial EVs (CEVs). Light- and medium-duty (electric trucks) ETs can be charged overnight using level 2 chargers, while small- and medium-duty ETs can be charged quickly using level 3 chargers. Additionally, some heavy-duty ETs can be overnight charged using level 3 chargers.  However, the majority of medium- and heavy-duty EVs with long driving distances need specialized fast-charging infrastructure with higher power capacities than the current fast level 3 chargers. As a result, several businesses, including Tritium, Phoenix Contact, BMW Group, and Charge Point, have revealed new plans to install high-power capacity charging infrastructure with a 400 kW or higher rating. Additionally, Tesla Inc. has revealed plans to expand its network of 1 MW mega chargers, each of which can travel 640 km in just 30 minutes. In accordance with the operational schedules of commercial EVs, charging infrastructure can be installed at locations where vehicles are parked (depots, yards, aggregators, etc.) to enable overnight charging or between shifts, as well as in open areas to enable charging along a commercial vehicle's daily route. Two proposed methods for charging commercial EVs are suitable: return-to-base model charging infrastructure and public charging infrastructure. Return-To-Base Model Charging Infrastructure The majority of commercial enterprises use a "return-to-base" strategy, where high-power charging infrastructure is installed at their commercial facilities (depots, yards, industrial micro-grids, etc.) to enable the full charging of electric trucks (ET) outside of working hours, such as overnight or between shifts, as shown in Fig. 1. This is due to the spatial and temporal distribution of commercial truck fleet activities and a lack of suitable public charging stations.  Installing a dedicated charging station for each ET that needs to be charged at the commercial facility is the easiest strategy to implement during the early stages of ET adoption. However, it is possible for several ETs to share a single charging station in order to lower the upfront cost of the infrastructure necessary for charging, provided that this decrease in the number of charging stations does not interfere with the ETs' operational schedules.Fig. 1. Operation model of the return-to-base strategy. Source: IEEE Access Charging at Public Charging Infrastructure Commercial vehicles should ideally be charged where they park, but for a variety of reasons, as shown in Fig. 2, it may still be necessary to charge them while they are on the road during their daily driving cycles. Particularly for small commercial enterprises, charging commercial vehicles while they are on the road can help to reduce the capital cost investment of charging infrastructure required at a parking area. The development of contact-free charging infrastructure, mainly inductive power transfer (IPT) charging systems, has been the subject of extensive research.  Installation of battery swapping charging infrastructure, which allows EVs to swap out their nearly empty battery bank for a fully charged battery bank, is another way to put electric vehicles on the road. Contrarily, conductive charging stations can be gradually sized and scaled up to meet the power needs of CEVs. Therefore, compared to other options, charging stations do not require as much infrastructure investment.Fig. 2. Operation model of public charging infrastructure. Source: IEEE Access Charging Infrastructure for Long-Haul Commercial EVs Large battery banks need to be charged at warehouses because long-distance commercial vehicles have large daily ranges. The payload ratings of long-haul vehicles, however, would be impacted by the weight of the large battery banks. For a few long-haul CEVs that are currently on the market, Table 2 displays the battery weight ratio of the total GVW. As can be seen, increasing battery capacity will result in a higher battery weight to gross vehicle weight ratio, which will lower the maximum payload capability.  According to an analysis, the maximum payload of long-distance CEVs is lower than that of commercial diesel vehicles, as shown in Fig. 3. This graph displays the weight distribution of the major parts for CEVs and diesel vehicles with various battery capacities. As can be seen, compared to diesel vehicles, the CEV's maximum payload is limited to a maximum of 23%.Table 2. The battery weight ratio of the total GVW of some long-haul CEVs. Source: IEEE Accessi The battery weight is calculated based on the energy density 0.125 kWh/kgFig. 3. Weight breakdown of main components for diesel vehicles and CEVs with different battery capacities. Source: IEEE Access In order to electrify long-distance commercial vehicles, the best possible combination of battery bank size and high-power public charging stations along a route is required. Due to the strict operational schedules of these vehicles, charging long-haul vehicles on the road presents numerous difficulties. The number of hours that long-haul vehicles may be operated each day before being required to take a break is subject to many regulations.  For instance, the Federal Motor Carrier Safety Administration, a division of the US Department of Transportation, sets a daily cap on the number of hours of service at 10.5 hours before requiring eight hours of rest. Similarly to this, driving is only permitted for a maximum of 4.5 hours per day and must be followed by a minimum of a 45-minute break. Therefore, as shown in Fig. 4, charging activities for long-distance vehicles must take place when the vehicle is at rest. To keep up with their operational schedules, long-distance vehicles will have to stop at places with lots of high-power charging stations. However, running multiple chargers simultaneously imposes significant challenges on the power grid, requiring expensive network reinforcement. Additionally, the stability of a grid system is impacted by these numerous charging stations, particularly during peak hours. These limitations have an effect on the number of vehicles that can be charged at a particular location and, consequently, the rate at which charging infrastructure is utilized. Fig. 4. Operation model of haulage trucks. Source: IEEE Access The right size and localization of charging infrastructure along highway routes will be necessary to overcome the aforementioned difficulties with charging long-haul vehicles. Electric utilities, fleet owners, and truck stops should work together to identify the best locations for the charging infrastructure while taking into account the reliability of the power systems and the schedules of long-haul vehicles.Summarizing with Key Points: Some of the takeaways from the article are as follows: SAE J1772 standard divides EV charging infrastructure into three levels based on power rate, voltage, current, and installation location. Levels 1 and 2 are slow chargers, while Level 3 is a fast charger.Tritium, Phoenix Contact, BMW Group, and Charge Point have announced plans to install 400 kW or higher charging infrastructure. Tesla Inc. plans to expand its 1 MW mega charger network, which can travel 640 km in 30 minutes.There are two suggested ways to charge commercial EVs: infrastructure for Return-to-base model charging and infrastructure for public charging.Return-to-base strategy is installing high-power charging infrastructure at their commercial facilities (depots, yards, industrial micro-grids, etc.) to fully charge ETs and reduce infrastructure costs. Several ETs can share a charging station.In public charging infrastructure, road charging commercial vehicles reduces parking area charging infrastructure capital costs. IPT charging systems, battery swapping infrastructure, and conductive charging stations have been studied.To charge long-haul vehicles, highway charging infrastructure must be properly sized and located. Electric utilities, fleet owners, and truck stops should consider power system reliability and long-haul vehicle schedules when choosing charging locations. This blog post is part of a full research article from IEEE Access.

Overview: Transportation electrification began with small electric vehicles and gradually entered into medium-duty and heavy-duty vehicle electrification. In this article, we will understand the importance of commercial vehicle electrification and the challenges ahead. Significance of Commercial Vehicles Electrification Global climate change has resulted from human-caused greenhouse gas (GHG) emissions, which have raised the earth's temperature over the past century. The 2016 Paris Agreement sought to reduce global GHG emissions in order to keep the average global warming within two °C above pre-industrial temperatures in order to combat this threat from climate change. The transportation industry, which produces nearly 25% of the world's CO2 emissions, is one of the biggest sources of GHG emissions. Road vehicles account for nearly 75% of all CO2 emissions in the transportation industry among all modes of transportation. Therefore, a crucial step in reducing direct CO2 emissions is the electrification of road transportation. Many governments have therefore established transitional plans to electrify their transportation sector by 2050. Around 10 million electric vehicles (EVs) were in use worldwide as of the end of 2020, with battery electric vehicles making up two-thirds of this total. These EVs are predominantly light passenger cars. Challenges in Commercial Vehicles Electrification Nearly 40% of the world's road transportation sector's CO2 emissions in 2015 came from commercial vehicles, and under the "business as usual" scenario, those emissions are expected to at least double between 2015 and 2050. Therefore, the electrification of commercial vehicles is a crucial research area because it offers a promising chance to significantly reduce these emissions. Due to the small size of electric vehicle batteries, their low mileage, and the lack of public charging infrastructure, the majority of studies on electrifying commercial vehicles have concentrated on the hybridization of these vehicles.  Light-duty trucks (LDTs), which have been successfully electrified without significantly altering travel habits, have been the primary focus of the initial deployment of zero-emission commercial electric vehicles (CEVs), including electric trucks (ETs). Heavy-duty truck (HDT) deployment is in the pilot stage, whereas the deployment of medium-duty trucks (MDT) is still in the early stages. According to recent studies, there have been around 2,50,000 light-duty commercial electric vehicle sales, including trucks, with a stock of close to 31,000 medium- and heavy-duty vehicles. When compared to light passenger vehicles, commercial electric vehicle adoption has lagged, which has been attributed to the unsatisfactory policies implemented in this sector. With the availability of suitable charging infrastructure that meets the charging needs of these vehicles, the possibility of electrifying commercial vehicles grows. Commercial vehicle drivers are unlikely to switch to electric vehicles if the charging process is more challenging, uncertain, and time-consuming. However, as can be seen from Table 1, there are a variety of uses for commercial vehicles, which also affects the average load, trip length, and daily mileage of these vehicles. Furthermore, compared to passenger vehicles, the operational schedules of commercial electric vehicles can affect how quickly these vehicles charge up at charging infrastructure. Table 1. Different applications of commercial vehicles. Source: IEEE AccessVMTi refers to Vehicle Miles Travelled,PTOii refers to Power Take-Off,Percentageiii The percentage of the truck population by vocations depends on California truck population. Recent Advancements in Commercial Vehicles Electrification  In contrast to diesel and alternative fuel trucks, however, recent advancements in lithium battery technology have made electric trucks both technically and financially feasible. Existing studies have examined the potential advantages of ETs over diesel trucks over a vehicle's lifetime. These studies have found that, despite the high upfront costs of ETs, they can perform at least as well as diesel trucks over their entire lifecycle, particularly if the latter have long battery lives and high annual mileage. Moreover, the use of ETs, particularly MDTs, and HDTs, has increased as a result of regulations and government incentives encouraging the use of zero-emission vehicles. With battery sizes ranging from 300 kWh to roughly 990 kWh, a number of truck manufacturers, including DAF, Daimler, MAN, Navistar, Nikola, PACCAR, Volkswagen, Volvo, Tesla Inc., and Thor Trucks, have made significant plans to electrify their MDTs and HDTs. Due to their short-range needs and compact batteries, MDTs have drawn the most attention from these announcements regarding electrification. All of the announcements have a model for medium-duty trucks, and some manufacturers, like Daimler and BYD, have already released their commercial trucks for certain markets. In their announcements, some manufacturers, including Navistar, Volkswagen, Thor Trucks, Freightliner, and Tesla Inc., have mentioned the production of HDTs.  On the other hand, a lot of businesses have started incorporating ETs into their fleets or have made an announcement regarding their procurement of ETs. For instance, Walmart Inc. reported 45 class 8 Tesla Semi HDT pre-orders for the coming year. Similar orders for electric delivery trucks were made by Amazon and Rivian in 2019, and Anheuser-Busch announced plans to use 21 HDTs from BYD in California by the end of the year. In general, commercial vehicles, such as trucks, can be divided into three groups based on their gross vehicle weight (GVW). LDTs fall into this category if their GVW is less than 3.5 tonnes (t), MDTs fall into this category if their GVW is between 3.5t and 15t, and HDTs fall into this category if their GVW is above 15t. Each category has a wide range of vehicle types appropriate for their range of occupational operations, such as long-haul freight and garbage collection trucks.  Due to policies encouraging the adoption of zero-emission vehicles and advancements in battery technology, the electrification of MDTs and HDTs has been increasingly adopted in recent years. MDT models with battery bank capacities ranging from 48.5 kWh to about 350 kWh and an estimated range of up to 400 km have been produced by numerous truck manufacturers. Many models of HDTs with battery bank capacities between 120 kWh and 1000 kWh to cover an estimated range of up to 800 km have been introduced or produced. Table 2 lists the specifications of some MDTs and HDTs that are currently advertised or reported. Table 2. Specification of some commercial electric vehicles. Source: IEEE Access The estimated range of CEVs and the availability of appropriate charging infrastructure determine whether or not they can be used to cover the daily travel distance of commercial vehicles. According to surveys, most medium-duty commercial vehicles travel an average daily distance of 80 km to 250 km, while heavy-duty commercial vehicles travel an average daily distance of up to 700 km. As a result, at locations where they park overnight or in between shifts, the reported range of medium-duty CEVs can cover a sizable portion of the daily travel distance with just one charging event per day.  However, some medium- and heavy-duty CEVs require high charging rates to be met in a single charging event over the times they are parked because of high charging requirements (such as long-haul operation, multiple-shift operation, etc.). A high percentage of the daily travel distance is covered by multiple charging events per day at various locations along commercial vehicles' routes due to the constrained capacity of some electrical power infrastructure, which restricts the charging rate of charging infrastructure. Therefore, the number of times a CEV may need to be charged each day will depend on the daily mileage of commercial vehicles, the CEV's estimated range, and the infrastructure's charging rate. Summarizing With Key Points: Some of the takeaways from the article are as follows: Transportation emits nearly 25% of the world's CO2 and GHGs. Thus, many governments have transitional plans to electrify transportation by 2050. As of 2020, there were 10 million electric vehicles (EVs), two-thirds of which were battery-electric. Light passenger cars dominate these EVs.Most studies on electrifying commercial vehicles have focused on hybridization because electric vehicle batteries are small, have low mileage, and lack charging infrastructure.If charging is difficult, uncertain, and time-consuming, commercial vehicle drivers will not switch to electrifying their vehicles.Recently, MDTs and HDTs have been electrified due to policies encouraging zero-emission vehicles and advances in battery technology.  This blog post is part of a full research article from IEEE Access.*******************************************************************************************************************************************

Executive Summary: 2026 UpdateNMOS (N-channel MOS) and PMOS (P-channel MOS) are the fundamental building blocks of modern CMOS technology used in processors and memory. As of 2026, the key distinction lies in their charge carriers: NMOS uses electrons (faster, smaller), while PMOS uses electron holes (slower, larger). Modern circuit design combines both to create low-power, high-speed logic gates. What is an NMOS Transistor?An NMOS (N-channel Metal-Oxide Semiconductor) transistor is a majority-carrier semiconductor device that uses electrons to conduct current between the source and drain when a positive voltage is applied to the gate. In 2026, NMOS remains the workhorse of digital logic due to the high mobility of electrons. These transistors serve as amplifiers, switches, or resistors in analog and mixed-signal integrated circuits (ICs).Key Characteristics:Charge Carrier: Electrons (High mobility).Activation: Conducts when Gate Voltage > Threshold Voltage (Logic 1).Application: Primary "pull-down" network in CMOS logic.NMOS Transistor SymbolWhat is a PMOS Transistor?The PMOS (P-channel Metal-Oxide Semiconductor) transistor operates inversely to the NMOS, using "holes" as charge carriers within an n-type substrate. While historically used independently, in modern architecture, PMOS is primarily paired with NMOS to form CMOS (Complementary MOS) circuits to minimize static power consumption.Key Characteristics:Charge Carrier: Holes (Lower mobility than electrons).Activation: Conducts when Gate Voltage is Low (Logic 0).Structure: P-type Source/Drain in an N-type body (N-well).PMOS Transistor Symbol How Does an NMOS Transistor Work?An NMOS transistor functions as a closed switch (ON) when receiving a high voltage (Logic 1) and an open switch (OFF) when receiving a low voltage (Logic 0).ON State (Logic 1 at Gate): When voltage is applied to the gate, it attracts electrons to the channel, creating a conductive path between the Source and Drain. Current flows.OFF State (0V at Gate): Without gate voltage, the path is broken. No current flows, effectively acting as an open wire. How Does a PMOS Transistor Work?A PMOS transistor operates with inverted logic compared to NMOS; it turns ON when the gate voltage is low and OFF when the gate voltage is high.ON State (0V at Gate): When the gate is grounded (Logic 0), holes accumulate in the channel, creating a "closed circuit" that allows current to flow from Source to Drain.OFF State (High Voltage at Gate): When positive voltage is applied, the channel is depleted of carriers, creating an "open circuit."In circuit diagrams, this inversion is represented by a "bubble" on the gate terminal. By combining PMOS (which passes logic 1 well) and NMOS (which passes logic 0 well), engineers create CMOS circuits, the standard for all modern computing processors from smartphones to servers.PMOS Transistor Operational Diagram NMOS Transistor Cross Section & StructureA typical 2026 NMOS transistor design (conceptually based on planar or FinFET structures) consists of a p-type silicon substrate sandwiched between two highly doped n-type regions (Source and Drain).The Body: The p-type body is typically grounded (0V).The Field Effect: As voltage at the Gate terminal rises, an electric field penetrates the oxide layer (Si-SiO2).Inversion Layer: This field repels holes and attracts electrons to the surface, creating an n-type "inversion layer" channel.Conduction: Once the voltage exceeds the Threshold Voltage (Vth), the transistor turns ON, allowing electrons to flow from Source to Drain.NMOS Transistor Cross SectionPMOS Transistor Cross Section & StructureThe PMOS structure is the physical inverse of the NMOS. It is constructed with an n-type body (or N-well) and two neighboring p-type semiconductor regions acting as Source and Drain.Operational Physics:The body is held at a positive voltage (VDD).When the Gate voltage is high (VDD), the PN junctions remain reverse-biased (OFF state).When the Gate voltage drops (towards 0V), positive charge carriers (holes) are drawn to the oxide interface. This creates a p-type channel, bridging the source and drain, turning the device ON.Note on Voltage Levels: While legacy TTL logic operated at 5V, modern 2026 processors use ultra-low voltages, typically between 0.6V and 1.2V, to reduce heat and power consumption in nanometer-scale transistors.Cross Section of PMOS Transistor CMOS Inverter: Combining NMOS and PMOSThe most fundamental digital circuit is the CMOS Inverter (NOT Gate). It perfectly demonstrates the synergy between the two transistor types by connecting a PMOS transistor to the voltage source (VDD) and an NMOS transistor to the ground (GND).CMOS Inverter CircuitLogic "0" Input (Low Voltage):PMOS (Top): Turns ON. Connects Output to VDD.NMOS (Bottom): Turns OFF. Disconnects Output from GND.Result: Output is High (Logic "1").Logic "1" Input (High Voltage):PMOS (Top): Turns OFF. Disconnects Output from VDD.NMOS (Bottom): Turns ON. Connects Output to GND.Result: Output is Low (Logic "0"). CMOS NAND Gate ArchitectureComplex logic like the NAND Gate relies on specific arrangements of these transistors. In a NAND gate, the output is Low (0) only if both inputs are High (1).CMOS NAND Gate CircuitTruth Table Analysis:Inputs A=0, B=0: Both PMOS turn ON (Parallel), Both NMOS turn OFF (Series). Output = 1.Inputs A=0, B=1: One PMOS is ON, One NMOS is OFF (breaking the path to ground). Output = 1.Inputs A=1, B=0: One PMOS is ON, One NMOS is OFF. Output = 1.Inputs A=1, B=1: Both PMOS turn OFF. Both NMOS turn ON, creating a path to Ground. Output = 0. I-V Characteristics of NMOSThe I-V characteristic curves define how the current (Ids) flows relative to the voltage applied.Linear Region (Ohmic): At low Drain-Source voltage (VDS), the transistor acts like a resistor controlled by the gate.Saturation Region: As VDS increases, the channel pinches off, and current becomes constant (ideal for amplification).I-V Curves: NMOS Transistor I-V Characteristics of PMOSThe PMOS I-V characteristics mirror the NMOS but operate with negative polarities (relative to the source). In modern digital analysis, we typically map the magnitude of current against voltage. Because hole mobility is approximately 2.5x lower than electron mobility, a PMOS transistor must be physically wider than an NMOS transistor to drive the same amount of current.I-V Curves: PMOS Transistor Key Differences: PMOS vs NMOS Comparison TableFeaturePMOS TransistorNMOS TransistorFull NameP-channel Metal-Oxide SemiconductorN-channel Metal-Oxide SemiconductorSource/Drain DopingP-type Regions (Boron doped)N-type Regions (Phosphorus/Arsenic doped)Substrate TypeN-type Substrate (or N-Well)P-type SubstrateCharge CarriersHoles (Slower mobility)Electrons (Higher mobility)Size EfficiencyLarger area required for same drive current.More compact; higher density.Switching SpeedSlower (due to hole mobility).Faster (due to electron mobility).Activation ConditionTurns ON with Logic 0 (Low Voltage).Turns ON with Logic 1 (High Voltage).Noise ImmunityGenerally higher noise immunity.Lower noise immunity compared to PMOS.Threshold VoltageNegative (Vth < 0)Positive (Vth > 0) ConclusionIn the landscape of 2026 electronics, the debate is rarely "PMOS vs. NMOS" but rather how to best integrate them into CMOS (Complementary MOS) architectures. While NMOS offers superior speed and density due to high electron mobility, PMOS is indispensable for creating non-dissipative logic gates that consume almost zero static power. Modern chip designs rely on symmetric operation where NMOS pulls signals down to ground and PMOS pulls signals up to VDD, ensuring robust, high-speed, and energy-efficient computation. Frequently Asked Questions (FAQ)What is the main difference between NMOS and PMOS?The primary difference is the charge carrier. NMOS uses electrons (negative charge) and turns ON with high voltage. PMOS uses holes (positive charge) and turns ON with low voltage. Physically, NMOS is built on a p-type substrate, while PMOS is built on an n-type substrate. Does PMOS have any advantages over NMOS?Yes. PMOS is essential for passing a "strong logic 1" (full VDD) without the voltage drop associated with NMOS pass transistors. Additionally, PMOS devices generally exhibit better immunity to electronic noise, which is critical in analog signal processing. Is NMOS preferred over CMOS?No, CMOS is universally preferred over pure NMOS logic. While individual NMOS transistors are faster, pure NMOS logic circuits consume power continuously even when idle (static power). CMOS combines NMOS and PMOS to eliminate static power consumption, drawing current only during switching, which is vital for modern battery-powered devices. Why are NMOS transistors smaller than PMOS?Electron mobility is roughly 2-3 times higher than hole mobility. To achieve the same current drive capability, a PMOS transistor must be made physically wider than its NMOS counterpart. Therefore, NMOS transistors are more area-efficient (smaller) on the silicon die. Why do we use PMOS if it is slower?We use PMOS to enable Complementary Logic (CMOS). Without PMOS, we cannot create circuits that have zero static power consumption. The "Pull-Up Network" in digital gates requires PMOS to actively pull the voltage to VDD when the input is low, ensuring distinct digital states and energy efficiency. { "@context": "https://schema.org", "@type": "Article", "headline": "NMOS vs PMOS Transistors: 2026 Comparison and Guide", "datePublished": "2023-02-09", "dateModified": "2026-01-05", "image": "https://www.apogeeweb.net/upload/pdf/20230209/NMOS Transistor Symbol.jpg", "author": { "@type": "Organization", "name": "ApogeeWeb" }, "description": "A comprehensive guide to NMOS and PMOS transistors, their working principles, cross-sections, and how they combine to form CMOS logic.", "mainEntity": { "@type": "FAQPage", "mainEntity": [ { "@type": "Question", "name": "What is the main difference between NMOS and PMOS?", "acceptedAnswer": { "@type": "Answer", "text": "The primary difference is the charge carrier. NMOS uses electrons and turns ON with high voltage. PMOS uses holes and turns ON with low voltage." } }, { "@type": "Question", "name": "Does PMOS have any advantages over NMOS?", "acceptedAnswer": { "@type": "Answer", "text": "Yes. PMOS is essential for passing a strong logic 1 (full VDD) and generally exhibits better immunity to electronic noise." } }, { "@type": "Question", "name": "Is NMOS preferred over CMOS?", "acceptedAnswer": { "@type": "Answer", "text": "No, CMOS is preferred. CMOS combines NMOS and PMOS to eliminate static power consumption, whereas pure NMOS logic consumes power continuously." } }, { "@type": "Question", "name": "Why are NMOS transistors smaller than PMOS?", "acceptedAnswer": { "@type": "Answer", "text": "Because electron mobility is higher than hole mobility, NMOS transistors can drive the same current with a smaller physical width compared to PMOS." } }, { "@type": "Question", "name": "Why do we use PMOS if it is slower?", "acceptedAnswer": { "@type": "Answer", "text": "PMOS is required to build the 'Pull-Up Network' in CMOS circuits, allowing for distinct digital states with near-zero static power consumption." } } ] }}

Catalog IntroductionComponentsArduino Code Introduction The idea of this project is to create an Arduino based home security alarm system that can be used to monitor and control the various appliances in the house. The main purpose of the system is to detect any unusual activity and notify the user about it in an efficient manner. The system will also use a web server to push notifications to mobile devices such as smartphones and tablets. The project consists of an Arduino Uno board connected to a Debounce shield which contains a piezo buzzer, LED, power supply and other components necessary for interfacing with Arduino Uno board. A passive infrared sensor, or PIR, is a Pyroelectric device that senses motion. For this reason, it is sometimes referred to as a motion detecting sensor. It may be able to detect motion by detecting variations in the infrared levels emitted by nearby objects. This gadget is a basic motion-activated alarm. Its brain is an Arduino microcontroller. It is connected to a PIR motion sensor, a buzzer, a resistor, and two external connectors. The system is very portable because it is entirely battery-powered. As soon as you get the code, you may link all of the external components. This is the easiest thing to do with a breadboard. To check everything out, you can create bogus connections.  The whole system Is powered by 12V DC power supply which powers all other components except Arduino Uno board itself. The MCU receives digital commands from Arduino Uno through SCI interface and sends appropriate analog or digital signals on its pin according to the command received by it. This project has been inspired by many previous projects that use Arduino boards for controlling various electronic devices such as lamps, lights etc., but this project focuses more on controlling various appliances. The Arduino Uno Is based on the ATmega328 chip, which has built-in USB support for serial communications. It also has a built-in 5V power regulator that allows it to be powered directly from the USB connection or from a battery. Components 1Arduino2Motion Sensor3LED’s4Buzzer5LCD Module Arduino Code#include  <LiquidCrystal.h>   int ledPin = 13;                int inputPin = 7;               int pirState = LOW;             int val = 0;                    int pinSpeaker = 10;           LiquidCrystal lcd(12, 11, 5, 4, 3, 2);                           void setup() {  pinMode(ledPin, OUTPUT);  pinMode(pinSpeaker, OUTPUT);  Serial.begin(9600);  lcd.begin(16, 2);  lcd.setCursor(2, 0);                                              lcd.print("P.I.R Motion");                                        lcd.setCursor(5, 1);                                             lcd.print("Sensor");                                              delay(4000);  lcd.clear();  lcd.setCursor(2, 0);                                              lcd.print("Displaying");                                       lcd.setCursor(2, 1);                                              lcd.print("A");                                         delay(5000);                                                      lcd.clear();                                                    lcd.setCursor(0, 0);      lcd.print("Processing Data.");      delay(3000);      lcd.clear();      lcd.setCursor(3, 0);      lcd.print("Waiting For");      lcd.setCursor(3, 1);      lcd.print("Motion....");     }void loop(){  val = digitalRead(inputPin);  if (val == HIGH) {                digitalWrite(ledPin, HIGH);      playTone(300, 300);    delay(150);        if (pirState == LOW) {      Serial.println("Motion detected!");      lcd.clear() ;      lcd.setCursor(0, 0);                                                 lcd.print("Motion Detected!");             pirState = HIGH;    }  } else {      digitalWrite(ledPin, LOW);      playTone(0, 0);      delay(300);         if (pirState == HIGH){            Serial.println("Motion ended!");      lcd.clear() ;      lcd.setCursor(3, 0);      lcd.print("Waiting For");      lcd.setCursor(3, 1);      lcd.print("Motion....");            pirState = LOW;    }  }}// duration in mSecs, frequency in hertzvoid playTone(long duration, int freq) {    duration *= 1000;    int period = (1.0 / freq) * 100000;    long elapsed_time = 0;    while (elapsed_time < duration) {        digitalWrite(pinSpeaker,HIGH);        delayMicroseconds(period / 2);        digitalWrite(pinSpeaker, LOW);        delayMicroseconds(period / 2);        elapsed_time += (period);    }}