Questions tagged [mosfet]

A transconductance (using voltage to control current) electronic component used for switching and amplification. Acronym for Metal-Oxide-Semiconductor Field-Effect Transistor. (from http://en.wikipedia.org/wiki/Transistor)

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Why don't inverters use BJTs to easily produce a pure sine wave?

This has been in my mind for a while now, I'm curious. Why not use a BJT H-bridge on the high voltage side, to convert the high voltage DC to AC. I saw a simple circuit that converts square waves to ...
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What's the problem with this four-transistors XOR gate?

I aimed to design a XOR gate using as few transistors as possible. Eventually, I came up with this: Designed and simulated here. The two terminals on the left are inputs, where the "low" ...
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MOSFET being driven by an Arduino won't turn on without a 1M pulldown resistor

I'm driving an IRFZ44N MOSFET from an Arduino Uno (pin D2) via a 220R resistor. On the drain, I have an LED with a protection resistor to +12V, and the source straight to ground. The Arduino is ...
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Touching or moving LED circuit board causes PWM to flicker momentarily. Without touching the board there is no flicker

The circuit shown is set up as a constant current drive. It turns on and off just fine. When it's fully on the MOSFET on the low side of the LEDs is fully on and doesn't get hot at all and is not ...
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Why we have positive voltages for ground/VSS supply?

I have seen circuit designs that use multiple power supplies/grounds, and some of the VSS ground supplies are non-zero, for example: 0.3V. I am curious to know why this is useful. Where is it used? ...
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Peak switching power in MOSFET as seen in LTSpice, and reduction using snubber or gate resistor

I am exploring a tentative design to limit current for charging a VFD bus link capacitor from the AC mains. Simple analog current limiters using resistors and transistors are inefficient and ...
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Are these MOSFETs wired correctly?

I have an ESP32 that I'm trying to use to control a motor and a water-level sensor. Both of these devices are 12 V DC, so I'm using a DC-DC converter that takes 12 V input and outputs both 5 V and 12 ...
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Powering two loads from either one or two sources

Both loads need to be powered at all times - V1 or V2 can be either both present or only one of them. Does this circuit look like it is going to make it happen? Instead of M1 and M2 there will ...
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What voltage will drive this MOSFET best?

I'm planning to use this MOSFET as on/off switches for various loads ranging from roughly 100 to 250VDC and 0.1 - 1A. I believe it to be more than adequately sized. I can also add quite a bit of ...
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Heat Problem with MOSFET Controlling a DC Shunt Motor

EDIT 3: This problem is solved. To anyone reading this after the fact, let it just be a lesson in making sure you are using working equipment. I'm a physics undergrad, not an engineer, so please ...
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Noise sensitivity to output impedances [duplicate]

A lower value of output impedance in a CMOS inverter leads to less sensitivity to noise of the inverter. Can someone elaborate regarding this? The quote comes from Digital Integrated Circuits by ...
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Why can't an MCU's GPIO pins directly control power MOSFETs?

I'm looking at electronic speed control circuit design, and notice that most use a driver IC like TI's DRV series of chips. At the moment, sourcing these chips is extremely difficult, so I'm wondering ...
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Are SMPS (inductor) current limits mostly thermal?

I'm building a boost converter that needs to boost 200A for 1 second and then shut down. The vast majority of reading I've done on SMPS and various PSU topologies assumes an RMS current and high duty ...
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How does a bootstrap capacitor power the gate?

I understand this circuit for the most part, but I am still confused on something. So lets say that the bootstrap capacitor is already charged from the bottom MOSFET being on previously. Then, a logic ...
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How is a highside gate powered with a bootstrap circuit and MOSFET driver?

I have been trying to understand this circuit, but I just don't get how the boot strapping works. Correct me if I am wrong but if I apply 400V at the drain of the high side MOSFET, the gate needs 410V ...
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Short circuit broke a P-channel MOSFET

I have an electronic board and I inadvertently made a solder bridge while soldering my circuit. This solder bridge is represented in blue on the picture below. After that the P-channel MOSFET ...
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How is MOSFET gate resistor chosen?

I have been doing research on MOSFETS. I see that in a typical circuit that includes a MOSFET and a Driver IC, there is a gate resistor. I have done research on this gate resistor and I am aware that ...
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Relays or MOSFETs

I’m making a circuit with peltier modules, a relay H-bridge and an Arduino. The system takes input from user of desired temperature. There is a temperature sensor placed on the peltier and the system ...
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Bi-directional current source based on MOSFET or IGBT

I am studying a bi-directional current source based on precision difference amplifiers and the MOSFETs, which is described on the website https://www.edn.com/simple-precise-bi-directional-current-...
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Replacing a dual N-channel MOSFET with another with different heat dissipation pads assignment

Trying to replace the FDMD82100 with an FDMS8090 used in a half-bridge circuit. The 82100 has S1 connected to D2 and the heat dissipation pads connected to D1 and S2. The 8090 has dual N-MOS with heat ...
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How do MOSFETs in 300-500A ESCs handle the current?

I’m trying to build an elecyronic speed control (ESC) for a boat that requires a massive amount of continuous current flow. I’m trying to also design the ESC my self. I need to supply 50 V and 300 A ...
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How is junction-to-ambient temperature measured?

Is the test done is still air (natural convection)? If I know junction-to-ambient resistance and max junction temperature, can I use it to directly derive heat loss? P=(Tjmax-Tamb)/Rja
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Driving an LC shutter using a solar panel

I am trying to drive an LC shutter using a solar panel. The particular LC shutter I am looking at is this one: https://www.adafruit.com/product/3330 Different voltage levels can be applied to this LC ...
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What does it mean 'leaded' near junction-to-case resistance?

See in the picture below. On a separate note, why does some manufacturer specify both junction-to-case and junction-to-lead resistance? On page 4 of this datasheet: https://www.infineon.com/dgdl/...
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Controlling a 12V solenoid lock with 3.3V - IRLZ44N

I would like to drive a solenoid lock from a 3.3 V MCU with a N-channel IRLZ44N MOSFET. Here are the specs and diagram: Solenoid Lock: 12 V – 2 A (K02-12V DC 2A Electric Magnetic) Below is the diagram ...
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Why does Vgs oppose the Vds in MOSFET? [duplicate]

I know Vgs is applied to form a channel and Vds is applied for drain current and when Vds is significant channel starts to reduce from the drain side because the difference in potential between gate ...
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Best practice power on/off switching with small switch in power electronic

I am developing an industrial project as an amateur but I have no experience in power electronics. I want to add an on/off button to a PCB design with 12-36V operating voltage and 3A load current. The ...
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Ensuring N-MOS is in triode region (high side switching)

I'm confused as how to use the n-MOS as a high side switch. I understand that the Vgs should be higher than Vdd enough to drive the FET into triode region (whether by means of a charge pump or gate ...
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Need help identifying SMD IC

I have a Network Video Recorder, Chinese one, NBD8016S-XC v2.03. I think it had an electrical shock after power outage, just want to try to repair it. I have found the IC that is burnt, but can not ...
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MOSFET Driver Base and Gate resistors and other input stage for PWM motor control

I have the below basic pwm circuit for speed controller of a 12V ~10A motor - I have seen this circuit but am unsure of how to select base or gate resistors. These should be to protect the gate from ...
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PWM IRF510 Mosfet Current very low

I have a PWM circuit board as shown below that is connected to a water canister. The purpose is to generate hydrogen bubbles. The setup is working but the production of bubbles is very low. The ...
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Is this current reading of my power supply correct?

I have built this simple ignition coil driver to test old ignition coils I have. I added R7 to match the drain to source resistance of the mosfet in my real circuit which is a p10nk70zfp. The drain to ...
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Tl494 with gate driver IC output voltage problem

Recently I've got my hands on some ETD42 ferrite cores and decided to make a 300W pure sine wave inverter. I chose the TL494 SMPS IC for driving the booster circuit (12 to 340V) and using the EG8010 ...
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5V 3A UPS using MOSFET switching between DC Main line and Power source

Working on DC UPS I have used 9V dc main source as well as power source using 2s3p 18650 lithium batteries UPS, and for switching purposes I have used MOSFET IRF9540. Can someone verify will the ...
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Help with power supply ORing circuit

I'm checking a system that has an ORing circuit to allow a battery backup for when the power supply is cut and it seems like a MOSFET (Q3) is backwards of how it should be. Vin=3.9 V (at LM66100), ...
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Is reverse polarity protection this simple?

I am working on a PCB design and need help understanding reverse polarity protection. The board will be powered with a 12V 5.4A power supply via barrel jack. I am planning on using this chip because ...
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1 answer
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Why use N-channel and P-channel MOSFETS with an ESC instead of just using N-ch MOSFETS?

I am following this build for an ESC. I don't understand why this build uses both n-channel and p-channel MOSFETS instead of just using N-channel MOSFETS because they are less expensive and easier to ...
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Where do you find how much heat a heatsink is rated for? [closed]

I have an N channel MOSFET and a P channel MOSFET. I found that for the P-channel MOSFET I need a heatsink that is lower than 5°C/W. The N channel MOSFET needs a heatsink that is lower than 13°C/W. I ...
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Using dual output LDO

I want to use this LDO: AP7346D-1828FS6-7. This LDO has two outputs and it has "Enable" controls. I want to connect these outputs 1.8V and 2.8V for one input. I can control this with EN pins,...
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Weird comparison between MOSFETs for ESC

I am designing an ESC (electronic speed controller) for a BLDC motor which is 3500W, 85A and 44V. The first thing is to choose the MOSFET, which should be easy. I first found the IRFS7534, which has a ...
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How to replace a 8 channel DIP switch with a chip that controls it digitally [closed]

There is a 8 channel DIP switch whose state i wanted to change dynamically using a microcontroller. I thought of using an array of mosfets that will do the job. Kindly suggest me a DIP package or a ...
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Miller effect in MOSFET

I have few question related to Miller effect in cmos. What does rate of change of Vgd (across Cgd) or Vd (drain point) depend on, when the transistor turns on? When transistor is on, it will get into ...
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How is the input capacitance and output capacitance different in a MOSFET?

I was reading this data sheet on a MOSFET. In this datasheet it says the "input capacitance" is 1470 pF, and the "output capacitance" is 360 pF. How is it possible to have a ...
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How to capture fast signal response from Gate beam IR sensor

I have purchased two IR RX/TX sensors. The datasheet is here. I have also purchased an ESP32 microcontroller. I want to use the beam in a way that every time someone walks across this beam (i.e. the ...
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Transistor to switch low voltages (< 1V)

I am building a system for pulsed electrodeposition, where I would like to switch very low voltages (0.3 - 1.0V.) I am not sure about the type of transistor to use for that. A BJT would drop 0.7V, so ...
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How do you choose the correct MOSFET for your project? [closed]

I am building an electric longboard. I am replicating this exact ESC circuit by GreatScott. The amount of voltage and current that will be going through my MOSFET's are 36V Max and 80A Max. I need 3 N-...
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How is it possible for GreatScott to use this MOSFET driver if it can only give 1.5 amps max?

I am trying to follow this tutorial by Greatscott. I don't understand how the TC4427 MOSFET driver he is using in this build works. I searched up the datasheet which can be found here. It says "...
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Help identifying SMD MOSFET for electronic speed control (ESC) - top markings DB08AC 8010

I am repairing a few MOSFETs on an ESC. The markings says DB08AC and 8010. The 8010 looks like maybe an OnSemi chip, but I am not sure as the logo does not seem correct. Can anyone help?
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I think I fried my IRF840 MOSFET, need help troubleshooting [closed]

I have recently unsoldered an IRF840 MOSFET, and I tried using it on my breadboard. I connected everything correctly being: 1V-drain, button-gate, LED-source. I tried running once, and it worked, but ...
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Is a dual-gate MOSFET different from a two MOSFETs connected source-to-drain?

Is there any other advantage of a dual-gate MOSFET other than combining two single-gate MOSFETs in the common source + cascode configuration in a single package? Does it have anything to do with ...
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