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Questions tagged [mosfet]

Metal-Oxide-Semiconductor Field-Effect Transistor, a type of field-effect transistor (FET). MOSFETs have an insulated gate, the voltage of which determines the conductivity of the device. This can be used for amplifying or switching electronic signals. (From: Wikipedia)

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Decreasing the input offset voltage of two stage opamp to below \$1 \: \text{mV}\$

I'm working on a two-stage opamp constituted by MOSFET transistors. The important specifications for this project are Open loop bandwidth of \$30 \: \text{MHz}\$ Closed loop gain of \$2\$ A standard ...
Carl's user avatar
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PWM Universal Motor Control

I recently posted a question about a circuit I had that wasn't working, and received some feedback indicating that most of my circuit was just... not good. Original post I drew up a new schematic, ...
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4 answers
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How does this gate driver generate 200 V from a 12 V supply?

How does this gate driver generate 200 V from a 12 V supply? And why when off does it never go below 50 V? ...
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Amplifier design using MOSFET

In designing an amplifier, I can have gain and make the MOSFET work in sat region, but the problem there is the \$V_{ds}\$ and \$V_{gs}\$ voltage was not designed. How can I make a more precise design?...
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Designing a 0.18-µm CMOS Multi-Stage MOSFET Amplifier (150 V/V Gain, 1-5 GHz) Without External Resistors/Capacitors

I'm working on a project to design a full-transistor-based (MOSFET) multi-stage amplifier using 0.18-ยตm CMOS technology. The requirements for the amplifier are as follows: Voltage gain of at least ...
Raczidian's user avatar
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Circuit Keeps Shorting the Drain - Source of my MOSFET

MOSFET datasheet Flyback Diode datasheet I'm trying to control a universal motor with PWM (generated by Raspberry Pi) modulating its speed. As soon as I switch the power on (115Vac mains), the motor ...
BoomSoon's user avatar
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IRFZ44N Datasheet read value problem

I'm having trouble with reading values from datasheet of IRFZ44N. How can I find the value of Vth or K-B(UnCox*W/L) value at an arbitrary operating point? I want to use MOSFETs in my design but can't ...
ali demir's user avatar
3 votes
5 answers
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MOSFET driver: Totem Pole or NPN Self-Biasing Turn-Off Circuit

I am building a project, where I want to drive some MOSFETs to control for example a 50W 12V LED and it brightness with a PWM signal from an ESP8266 with a frequency in the range of 1-5 kHz. I found ...
DeltaLima's user avatar
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2 answers
62 views

How to reduce propagation delay and mitigate dual-step transition

I am working on a circuit intended to protect digital output pins from the external voltages of the system on which they are designed to be used. I have built the circuit and found some "strange&...
Cheche Romo's user avatar
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PWM with PIC817 driving MOSFET seems to be too slow (LED dimming)

I want to drive a MOSFET (IRFZ44N) with an optocoupler (PC817) to control the brightness of an 50 W 12 V LED. The PWM is generated by an ESP8266, 1 kHz. Following schematic is used: In general it ...
DeltaLima's user avatar
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How can I simulate driving a high capacitance MOSFET with a gate driver IC?

I'm trying to drive a MOSFET with approximately 2nF of capacitance, using a 1EDN7511B gate driver. Following the data sheet sample circuit, I created this: and tried to simulate it on LTSpice using ...
SRobertJames's user avatar
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Low-Side Driver Not Sourcing Current from Load to GND

I have a circuit with an electronic load in parallel with an optocoupler and a low-side N-channel MOSFET connected to the circuit. The low-side N-channel MOSFET driver is supposed to source current ...
zsch3000's user avatar
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1 answer
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Electric field in power transistors

I had a question about power transistors, why are small fields used in power transistors? I think this question could be because the voltage is high, but mostly in terms of the transistor structure I ...
Sajadi's user avatar
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Using an Active Inrush Current Limiter as an Alternative to a Pre-Charge Circuit in EVs

I'm currently working on a master's thesis during an internship at an automotive company that manufactures EVs. The thesis focuses on improving a pre-charge circuit for an EV. In EVs, a pre-charge ...
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Output Noise of MOSFET with parallel current source

How can I calculate output noise voltage of the given circuit? Noise contribution of the M1 to output noise current: $$4kT\delta g_{m1}$$ Noise contribution of the RG to output noise current: $$4kTR_G[...
Aldrich Taylor's user avatar
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How to calculate the output impedance of a gain-boosted biasing circuit [closed]

I've been working on calculating the output impedance \$R_{Out}\$ โ€‹of the gain-boosted biasing circuit shown in picture, where all transistors are in the saturation region. While I understand the ...
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Simple cascode biasing problem in an electronic circuit

use variable (๐ผ_๐‘…๐ธ๐น, ๐‘‰_๐‘‡๐ป,๐‘‰_๐บ๐‘†) to express the range Assume that all 4*(W/L)1= (W/L)2= (W/L)3= (W/L)4= (W/L)5= (W/L)6 All TRs are under saturation region Assume that M2 is under subthreshold ...
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How large would my heatsink need to be for the IRLB4132 at 12.6 V and 60 A

I'm building a power distribution board (PDB) for my drone, which is powering 4 ESCs and an Arduino 33 BLE Sense Rev2. Iโ€™m using a 3s LiPo battery which provides 12.6V at max charge. My ESCs are rated ...
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How to model MOSFET in a continuous manner in circuit simulator with Early effect?

I'm implementing a power electronics circuit simulator. Currently I have all linear components including capacitors/inductors/transformers, switches, and as the only nonlinear component Shockley diode....
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H-Bridge with inductive load default state

I am developing a circuit for controlling solenoid valves and i am using H-Bridges (composed of PMOS and NMOS transistors). My question is whether it is important, when the H-Bridge is in its default ...
irag10's user avatar
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Soft-start circuit for highly resistive load - negating initial voltage spike

I am trying to design a soft-start circuit for one of my projects which has a relatively large resistive load (~1MOhm). I found the following example circuit from an answer for a previous post (12 V ...
Curious's user avatar
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The problem with hysteresis is in the comparator circuit with a mosfet. Oscillations during switching

In one of the design guides, I came across a circuit of a comparator with hysteresis. I modeled it in LTspice and built the circuit as shown in the figure. However, when I tested it with real ...
Typeof undefined's user avatar
6 votes
2 answers
312 views

Are my power calculations on this MOSFET Power Amplifier accurate?

Thanks to the help of electronics.SE, I've designed my first power amplifier, intended for transmitting CW on 7 MHz. Before I order parts and build it, I'd request a design review. One important note:...
SRobertJames's user avatar
1 vote
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32 views

Load is switching between 0V and overcurrent in the pulsed drain biasing circuit for a Power Amplifier

Given below is a block diagram of an evaluation-board. It is a pulsed biasing board to a PA. It is designed to produce a pulsed-drain and pulsed-gate signal for the biasing of GaN Power Amplifiers. I ...
Sahasra Vaiishnavi's user avatar
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ULP circuitry for a telematics unit

I am in the process of developing an ultra-low-power input circuitry for a telematics unit. The device will be connected to 24V truck battery and should be completely disconnected from the battery if ...
user14665305's user avatar
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1 answer
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Peltier cooler driving circuit

To prevent closing as duplicate immediately, there is the list of the most relevant questions: How to drive a Peltier element? Driving a Peltier w/ PWM or analog out Driving a Peltier element with ...
Suthiro's user avatar
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switching 2 mosfets with 1 signal

Hi. I'm trying to switch between 2 LED with 1 GPIO and not sure if I've designed correctly. C2_CC_CTRL = GPIO i wonder when GPIO signal is "high", Q14 MOSFET = "ON", D29 LED = &...
3clocks's user avatar
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Dot parameters LTspice - Transconductance of MOSFET

Below is a very simple circuit to extract the transconductance value of the MOSFET. As it is known, transconductance is known as Delta (Id) / Delta (Vgate). For the gate voltage, I defined it as .step ...
Mhan's user avatar
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Why does pinch-off occur in a MOSFET?

Considering an n-channel MOSFET with the source and the substrate at the same potential and the drain at a higher potential, although the potential difference across the oxide layer decreases along ...
Qwertyuiop's user avatar
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2 answers
41 views

How to drive P-Channel MOSFET For Highvolatge Precharge Ciruit in BMS Application

I am designing a BMS for 24S NMC (100.8 V) and looking for perfect solution for precharge on high side. I designed this circuit. It would be awesome if you folks comment on this and please let me know ...
Ajay Panwar's user avatar
-1 votes
0 answers
74 views

Ford Model T/A Voltage regulator, P-Ch MOSFET blows up

I'm hoping someone might have some insight into why I keep blowing up mosfets (like 20 so far). The circuit is a SIMPLE voltage regulator. The 100+ year old (100 watt max) constant current Model T (...
Jeff Stevenson's user avatar
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2 answers
65 views

Does a MOSFET draw current from its gate?

I understood that a MOSFET does not draw current from its gate, and only depends on gate voltage. However, this simple MOSFET circuit shows that when R1 is very low (1 ohm), it works fine, but when ...
SRobertJames's user avatar
5 votes
3 answers
383 views

MOSFET Operational Amplifier

I am confused. Why we always say that the gain of an op amp should be as large as we can? Supposing that an op amp has a power supply of 1.8ย V, the voltage gain is 1000ย V/V. If we give a small signal ...
jsdklfsldn's user avatar
1 vote
1 answer
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SMD SOT-23-3 Part identification - top marking 3D sideways 9

I have a Lenovo Legion 7-17imh05h laptop that had a short on LVDS cable and I found that the part attached in the image is cracked and has various marks indicating that it has been burned. The part is ...
J1and1's user avatar
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2 votes
1 answer
75 views

What is the relationship between Vgs and timing of a MOSFET?

Why when the Vgs is increased the rise/fall and delay time decreases? Isnt increasing Vgs increases the Qg and this should increase the timing and not the oposite. As you can see the timing at Vgen=...
Tintin's user avatar
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1 vote
1 answer
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MOSFET Total Gate charge graph (Qg)

Below is a Vgs -Qg graph of the IXTH88N30P N-channel MOSFET. Datasheet: https://www.mouser.com.tr/datasheet/2/240/media-3322045.pdf As seen in the graph, this curve is given for Vds = 150 V, Id = 44 A ...
Mhan's user avatar
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How to select resistors for MOSFET Gate terminal?

I need to design Buzzer circuit. While i searching for reference design in google i saw one design based on buzzer, Here they drive a buzzer by using MOSFET. Here My doubt is, they used R23 & R24 ...
Kuralmozhi's user avatar
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1 answer
82 views

How to improve mosfet switching timing?

I am a hobbyist and I am not a native so bear with me please. I was looking for a fast mosfet and by looking at some datasheets I noticed that switching time is not a constant parameter like this one: ...
Tintin's user avatar
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0 answers
69 views

How does CAN transceivers output CANH=3.5V and CANL=1.5V? [duplicate]

This is a questions that has been asked but did not find a clear answer. How it is the 3.5V achieved on CAN_H? Assuming there is 0.5V voltage drop on the internal diode, 0.1V on the internal MOSFET ...
Florin Adrian's user avatar
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Triggering a small black powder charge with an STM32

I am trying to design a flight controller system that can trigger some small low-power explosive charges as described here. The description states that the charges will ignite with as little as 2V at ...
Jark's user avatar
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-1 votes
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What specs should i look for for a mosfet in this project? [closed]

I am a hobbyist and not a native so bear with me. I need a MOSFET that can switch at ~ 100 MHz and withstand up to ~ 40 V and 40 A with a variable duty cycle. If my calculation corrects 1/100 MHz ...
Tintin's user avatar
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How do i make PWM be in the middle of the other one

Sorry if I worded my question wrong, I don't know how I should describe it. I'm making an inverter circuit for my class project. This is my MOSFET driver circuit: This is the output: The 2nd PWM ...
I like custard's user avatar
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50 views

differential gain for mismatched \$g_m\$ in differential amplifiers

I couldn't understand how the author came up with the expression of differential mode gain. He states to look from the Fig 4.17 to derive this expression, whereas the fig 4.17 has no mention of \$R_{...
wolff's user avatar
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Gain bandwidth calculation of two stage op-amp

I want to design a two stage single ended OTA without using a Miller compensation capacitance. Every source that I have examined gives a design example with a compensation capacitance. Hence, they ...
Aldrich Taylor's user avatar
3 votes
5 answers
783 views

How much current can a 2N7000 MOSFET guaranteed switch with 3.3V logic

I still have problems to interpret the datasheets of MOSFETs. I have a 2N7000 from UTC (datasheet here). How much current can I guaranteed switch when I only have 3.3V from an Arduino? In my ...
Tintenfisch's user avatar
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1 answer
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Diode Connected PMOS Doesn't Fully Activate

I'm very new to electrical and am trying to understand a diode connected PMOS. I am supplying 3.3V to the source and have tried varying loads after the drain of 220, 10k, 100k, 650k, 1.2M ohms. What I ...
Jared's user avatar
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1 vote
3 answers
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Can I Exceed a N Channel MOSFET's -Vgs Rating When Using It as a High Side Switch

This is a follow-up to a similar question I asked recently. Let's say I'm using an N-Channel MOSFET with Vds(Max) of 30v, Vgs(max) of +- 20v, and Vgs(th) of 2v. I want to use it as a high side switch, ...
Vera Fodor's user avatar
1 vote
2 answers
92 views

High Side N Channel MOSFET Switching

I have a project where I need to be able to switch a 24v solenoid with a 28v discrete signal. I would like to use high side switching where 28v turns on the solenoid and 0v turns off the solenoid. ...
Vera Fodor's user avatar
-1 votes
0 answers
60 views

Switch Realisation MOSFET in Push Pull Converter

I am doing the power electronics course at my university and am having troubles with the MOSFET switch. The MOSFET switch should conduct reverse current even when the gate is not biased (MOSFET is off)...
Mohammed Osama's user avatar
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1 answer
48 views

No voltage difference between driven MOSFET gate and floating drain/source

I'm measuring the voltage of a discrete MOSFET using a multimeter. The gate is connected to the output of a logic circuitry, while drain and source are floating. The voltage difference between drain/...
Darsh Oian's user avatar

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