Questions tagged [mosfet]

An 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)

Filter by
Sorted by
Tagged with
-1
votes
1answer
39 views

Falstad - a bug with mosfets?

I have a schematic in Falstad. It is almost symmetrical (the mosfets are connected by drains and "SWAP D/S" is enable in the second mosfet to be able to connect both). And this symmetrical ...
0
votes
1answer
38 views

SparkFun Power Driver Shield Kit for controlling 60 V input

I just bought SparkFun Power Driver Shield Kit. I read in the specifications that it was possible to control up to 60 V using PWM. I have got a project where I need to control 60 V with the PWM so I ...
0
votes
2answers
36 views

Problem when using MOSFET to switch on/off voltage regulator

I initially designed a circuit with a P55N06 MOSFET that would be used with a LM7805. The drain is fed by 9V, the source connects to the 'in' pin of the LM7805 and the gate is fed by 3.7V. The ...
0
votes
2answers
80 views

How to fix my simple MOSFET power switching circuit?

In my design the goal is to create a simple switch between power sources using a MOSFET. J2 is just a connector for the main power source which remains connected VDD is connected to a USB port VREG ...
0
votes
0answers
35 views

The simplest way to keep n-channel mosfet saturated by positive feedback

Actully it will be one way switch for a lamp based on photo-resistor input: To keep the mosfet saturated in the moment it turns on I need positive feedback. How to get it in the simplest way? I can ...
0
votes
2answers
135 views

MOSFET as a switch failed after 200k cycles - root cause?

The following is a schematic for a solenoid that failed after ~200k cycles. I found that the MOSFET drain to source failed short. I am getting~ 26 ohms resistance. The way this circuit works is as ...
0
votes
3answers
86 views

MOSFET Drive npn/pnp

I want to drive a MOSFET gate with about 10V. I use the following circuit as described in Fig. 4 http://tahmidmc.blogspot.com/2012/12/low-side-mosfet-drive-circuits-and_23.html Is this okay? How do I ...
0
votes
1answer
39 views

magnetic rotary encoder 0.3V output voltage

I have a 24V DC motor with a magnetic rotary encoder. The encoder has a 5V supply voltage. The datasheet states that it has an output voltage of 300-700mV. I have also measured it, and it gives around ...
0
votes
1answer
62 views

Standalone current limiting circuit for Ultracap banks

I've been experimenting with ultracaps for a while now and I have a very specific problem: I use the ultracapacitors to compensate for line inductances and general power filtering. When I install a ...
2
votes
3answers
110 views

One transistor versus two transistors as a switch

Why does the led dim first and then switch off when I use one transistor as a switch, but directly switch off when I use two transistors as a switch? These are the two circuits:
1
vote
1answer
85 views

What does this MOSFET do in this voltage regulation circuit?

In the below schematic, V_USB is connected to the +5V of a USB jack, that the user can plug and unplug. There is also a backup LiPo Battery, whose positive terminal is represented by V_BATT. From my ...
0
votes
1answer
67 views

What should I use to make this MOSFET drop the gate-voltage even faster?

I'm trying to create a delay circuit like this. When I snapp on the push button, then the current flows from +3.3V to GND and bypass the 220 Ohm resistor, which is my load. But the problem here is ...
0
votes
1answer
51 views

Can I use 1 optocoupler to drive 4 MOSFETs?

I've this circuit and works correctly, now I need to control 4 MOSFET instead of 2, is the second schematic correctly?
1
vote
0answers
34 views

Level-shifting with limited ways to change the board

I have this circuit: simulate this circuit – Schematic created using CircuitLab Where: U1 is an MCU powered at 3.3V OUT is a GPIO the dashed box represents an external hardware that I cannot ...
0
votes
3answers
43 views

Using a NMOS as High Side Switch for 48V battery

I am evaluating IR2125 and IRS20752LPBF and IR2184 high side gate drivers to drive a MOSFET that is to be used as a battery switch for a 48V battery, the continuous current from the battery is around ...
0
votes
0answers
14 views

MOSFET REPLACEMENT 60R580P

My Samsung 43 inches plasma display blown the main fuse, i am suspecting that two MOSFETs, what mosfet can i replace 60R580P with I see one is measuring continuity and feel replacing all is better, ...
1
vote
2answers
37 views

What's a good resource with lots of problems on MOSFET circuits? [closed]

I'm looking for a book/resource that focuses on MOSFET circuits like Common source/gate variations, Differential pair circuits, current mirrors etc. with TONS of problems and questions.
3
votes
2answers
36 views

Depletion Region Capacitance in MOSFET

Hi, I would like to ask about the behavior of a MOSFET as a capacitor, particularly at the onset of inversion/weak inversion - see Fig 2.6(c) At this stage in Fig 2.6(c), there is positive charge at ...
0
votes
0answers
34 views

buck small signal modelling

I have a synchronous buck converter and my inductor current looks like this:- To add voltage-mode closed loop control, I need to do the small signal modelling of the converter. I am a bit confused if ...
0
votes
3answers
42 views

High-Side N-Channel MOSFET Driving

Is this an acceptable way to drive a mosfet? In this case, I'm trying to turn on a high current load, but in case the load is changing it's resistance/impedance, or in the possibility it's ...
1
vote
1answer
47 views

Bidirectional voltage and current switch using mosfets

I'm following this tutorial (spanish) which tries to create a bidirectional power switch usng mosfets based on this publication by texas instruments The concept of the circuit looks simple enougth to ...
2
votes
2answers
126 views

Suitable Half Bridge Driver to control capacitve load

I am looking for a method to reliably and quickly charge/discharge capacitors. Each capacitor should be individually charged/discharged. The charge/discharge rate should be in the microsecond range (...
1
vote
0answers
39 views

Why charge injection happens

When a MOSFET switch is turned off and goes from sample mode to hold mode, the channel charge exits between the source and drain terminals. My confusion is, why can't some of the charge go back into ...
5
votes
5answers
776 views

Hard temperatures rises for a MOSFET

I'm a mechanical engineer and a high school teacher that is about to start mechatronics and electronics. I've built this simple circuit that has the purpose to switching on and off a 12 V / 25 W lamp ...
3
votes
2answers
331 views

MOSFET terminology seems to vary in every article i read!

For someone trying to learn about FET's, it seems there is no consistency in terminology (unless i am reading things wrong?) Trying to understand a FET as a switch (for power applications). It has ...
0
votes
1answer
92 views

Half-bridge gate driver fried, how can I make my design work?

I made a half-bridge following the recommended schematics from the IRS2184 datasheet. However when I powered it, it triggered over-current and got quite hot. Here is are schematic and routing. I ...
0
votes
0answers
40 views

How do I find the right MOSFET for my class E amplifier? [closed]

I'm trying to build a class E power amplifier for my Tesla coil right now. The operating frequency is 4MHz, Vcc is 50V and the output power should be around 100W. I've used Sokal's QEX article to ...
0
votes
0answers
32 views

Isolated discrete GaNFET driver implementation for flyback converter, 500kHz [closed]

I am about to embark on a project of making a discrete GaNFET driver. It should be isolated with a signal transformer. Do you have any suggestions for literature or designs? Below is my current ...
0
votes
0answers
28 views

If I drove pin DP8 high, would the MOSFET Q1 let current pass?

I have this circuit in my hand. If I drove pin DP8 high, would the MOSFET Q1 let current pass or would it not let it? I also have the same question for DP9. What would happen if I drove the pin DP9 ...
1
vote
1answer
31 views

How do I cutoff power to ultrasonic HC-SR06 when it is not been used, to save power

I want to read an ultrasonic sensor data every 10 minutes and expect that the module should be turned off in order to save power. How do I do this? I tried with a BC547 and PN2222 transistor but I end ...
2
votes
1answer
43 views

Pi Zero / GPIO Pins / +12V Power and Sharing Ground

I need a sanity check on my schematics before I pay for JLCPCB to make my PCB board. Goal: To have my Pi Zero fire a pyro charge in a model rocket. Setup: GPIO-20 Sends a signal to the MOSFET Gate, ...
-6
votes
1answer
58 views

How do use a MOSFET for automatic switching? [duplicate]

I'm trying to make an oscillator, but I can't wrap my head around the MOSFET. I have a very simple circuit (drawn in a cellphone paint app) where the circle with an arrow pointed at it is the MOSFET. ...
0
votes
0answers
39 views

Bode plot in Pspice

I want to get the bode plot of the controller part of my Buck converter. For this I looked online and saw a technique that mentioned to add an AC injection source from the voltage output to the top ...
1
vote
1answer
62 views

Transistor switch with capacitive load

The goal I would like to know how to connect a transistor (MOSFET) to a capacitive load. I would like to rapidly charge and discharge a capacitor. How do I do it correctly? I basically want the ...
0
votes
0answers
31 views

MOSFET current at very low temperature (4K)

I am trying to model the current at low T. To do so I need to compute the integral between the fermid diract statistic and the conductivity, with respect to energy. My problem is that I cannot ...
0
votes
3answers
119 views

P-Channel MOSFET has a really high voltage drop

I just got a new P-Channel MOSFET FQP47P06. In the datasheet it says it has an RDSon of 26 milliohms, Vgs(th) of -4V, and a max current of 47A, but when I hooked it up in a simple test circuit like ...
1
vote
1answer
37 views

Flip Flop Switch for a Rocket

I am looking for the best (closest) way to create a solid state version of a dual coil latching relay. Essentially, a circuit that has two inputs (on & off) that when pulsed will flip flop the ...
0
votes
1answer
38 views

What factors affect the threshold voltage in MOSFETs?

Does orientation of the MOSFET devices on a chip affect the threshold voltage similarity (matching?) What are the factors affected by different orientation.
0
votes
2answers
33 views

PWM Control 24V Circuit with 3.3V ESP8266 NodeMCU

I want to control some white led lights (datasheet) with PWM. The Leds are in a parallel-series circuit with 3 leds per series and multiple of those in parallel. (See Image below) The Leds itself are ...
0
votes
1answer
83 views

Trying to understand MOSFET Turn on Procedure

I am trying to understand the mosfet turn on procedure. This is from the following application note by TI. https://www.ti.com/lit/ml/slua618a/slua618a.pdf?ts=1613979703351&ref_url=https%253A%252F%...
1
vote
1answer
128 views

Does it matter to which ground you connect a MOSFET?

I'm a beginner when it comes to electrical engineering and recently started a project where I build my own portable bluetooth speakers. I already have a rough layout of the whole thing. I basically ...
1
vote
1answer
74 views

Which of these is the correct wiring of an RGB light strip with n-channel MOSFET for Arduino

In these 2 examples, they connect the source to the gate with a 10K resistor, and both source and gate are connected to ground (edit clarification: gate connects to ground via 10K resistor - source ...
0
votes
1answer
31 views

Pspice giving wrong results

I have a ZCS buck circuit which I simulated on PSIM first, and wanted to simulate it in Pspice now with the real components. However, I am getting wrong results in Pspice, and I can't figure out why. ...
0
votes
1answer
47 views

implement MOSCAP in an FPGA (or another digital IC)

Can I implement MOSCAP in an FPGA? I mean can I connect drain and source of a transistor to gnd and gate to another node? It can be another device other than FPGA. Thank you.
1
vote
4answers
411 views

MOSFET Drain - Source Current limiting

I am a new enthusiast to MOSFETS. I am trying to use a MOSFET to switch on and off a electromagnet that draws 5 amps at 1.2 volts using an Arduino. The circuit I am using has a diode going from the ...
1
vote
0answers
35 views

Correcting non-linear response of 5050 RGBW LED strips

I'm a non-engineer asking this question. I'm using a so-called 5050 RGBW LED stips for a project. The level of each colour is controlled by a mosfet transistor (IRLZ34N) which is in turn modulated by ...
0
votes
0answers
56 views

Will this MOSFET be on under these conditions?

I'm designing a circuit to control power going to a heater. I'll be using this n-channel mosfet. My intended voltage values are: 1 is at 24 VDC for both circuits. I want the mosfet to be on when 3 = 3....
2
votes
0answers
30 views

MOSFET diffusion to substrate capacitance

in order to eliminate body effect one way is to connect the substrate to source when the well is for a single device (PMOS with a well in a CMOS for example) , but i read that it increases the source ...
1
vote
1answer
127 views

Solid State Relay using photovoltaic MOSFET driver

I am in the process of creating a High power Mosfet based SSR. The idea is using a photovoltaic MOSFET driver such as VO1263 (SIlabs have similar IC but it uses CMOS coupling to create the isolated ...
0
votes
1answer
53 views

Best way to simulate a load in Circuit Simulator

I'm a bit new to simulating circuits and I'm looking for advice on the best way to simulate a load. I'm trying to build a current limiting circuit, using a current sense resistor and a set of ...

1
2 3 4 5
98