Questions tagged [fet]
Field Effect Transistor, a transistor in which most current is carried along a channel whose effective resistance can be controlled by a transverse electric field. Commonly used types of FETs include the Metal Oxide Semiconductor FET (MOSFET), and less common in recent designs, the Junction Gate FET (JFET or JuGFET).
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Numbers on a Field-effect transistor
I'm looking for a transistor and managed to find a number of them online however there is also a number at the top which I don't know what it means.
i.e this is what I found online:
https://m.media-...
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Can anyone explain this circuit, how these common drain FETs in series works?
Please I need help in this circuit. Where series FETs common drain configuration used. How it can be operate? If one FET is turned on then how another FET allow current? How the battery draw current ...
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How Series FET connected opposite to each other operates? [closed]
Two FETs are connected in series opposite to each other. See the following circuit diagram. I am confused here that when both FETs are turned on, How does it allow current to flow? but in the ...
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How this FET driver works? [closed]
Everyone, please guide me through this circuit. How this circuit is working.
The PACK+ and PACK- pins can be connected to a charger or load terminal. And the BAT+ and BAT- pins can be connected to a ...
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Transformer-coupled low noise amplifier
A rather common way to make a low noise amplifier with an equivalent input voltage noise density in the range of ~0.1 nV/rtHz, is to take a FET and place a step-up transformer in front of it.
I have ...
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How can I identify an IC marked '32D FD'?
I need to find the IC name of this marking number. It looks to me SOT-23 package. It is most probably an FET IC used for PWM dimming control of an LED driver. I am attaching LED driver schematic from ...
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MOSFET current direction
What is the direction of conventional current in a N-Channel MOSFET? What I think is it's from Drain to Source inside the transistor which means externally(in the external circuit) it will be the ...
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Seeking Advice for Upgrading Brake Control System with PWM [closed]
I'm working on improving our system's mechanical brake control mechanism. Currently, the brake is controlled by relays, but there are issues with oscillations (because it is a sudden and not smooth ...
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What would happen to the drain current of a D-MOSFET at cutoff voltage when we are going to plot the tranconductance curve?
Here,
$$I_{DSS} = 8 \,\textrm{mA}$$
$$V_P = -6 \,\textrm{V} $$
Equation for the drain current,
$$ I_D = I_{DSS} \left(1 - \frac{V_{GS}}{V_P}\right)^2 $$
So, the cut-off voltage is where the Drain ...
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Why does the substrate of a MOSFET need to be lightly doped?
Image source: Electronics Tutorials - The MOSFET
MOSFETs were briefly discussed in my advanced materials class last semester and after reviewing the material, I was confused why does the substrate ...
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Pull-up resistor is running slowly (inverting MOSFET circuit)
There's a problem with my fan control circuit.
It works well, but when I first power up the circuit, the fan runs for about 0.2 seconds. The reason seems to be the time until the pull-up resistor is ...
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FET driving by NPN issue (PWM)
I am having a few problems regarding a simple FET PWM driver. I am aware this circuit does not adhere to the best design practice, but I am in a situation where the design cannot be changed.
I have ...
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Connecting FETs to make a push pull GPIO
We have a circuit that generates pulses via GPIO. We use FETs for the push-pull mechanism.
Our schematic:
Description of the ...
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To BJT or not to BJT: That is the question [duplicate]
Practically speaking, when is it better to use a BJT vs a FET for swtiching (not as a linear amp)?
Given that FETs have both N-channel and P-channel forms, and BJTs come in NPN or PNP, it seems that ...
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Design of a band-pass filter with automatic gain control using a JFET
I have implemented this circuit which is supposed to do AGC and filter out the signal between 20 Hz-20 kHz, but it seems have some problems. The bandpass filter works well, but the agc circuit doesn't ...
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How to choose a "good" 3.3 V LDO and FET for low power applications?
I am trying to design my first low-power PCB using an ESP32 to switch a 12 V 1.2 A LED Strip.
I purchased this module that charges a Lithium battery using a solar panel here. Hence that is where the 5 ...
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FET AM modulator
I have been meddling with a FET-based AM modulator. I implemented a basic circuit as attached here along with its output. Is the output as it should be? If not, what am I doing wrong, and how can I ...
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Building a working OFET
Currently I am doing some research on OFETs (rather on the organic part) and I’m fairly new to the construction of the devices and on electronics in general.
None of the devices that I have built seem ...
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Using a Zener diode MOSFET gate voltage control circuit
I have a little problem with my simple project.
I want to control a 24V / 4A blower motor.
It works okay, but the MOSFET gets too hot.
I used a Zener diode to make the gate voltage above 12V, but it ...
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FET amplifier from 100 kHz to 100 MHz
I studied electronics a long time ago (and forgot almost everything) but now I would like to create a FET amplifier up to 100 MHz of extremely small signals (e.g. 1nV or even smaller). Signals are so ...
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PMOS with floating source
I'm trying to understand this example schematic from the LTC4007 datasheet. It all makes sense for the most part.
My question is around Q1, which is a PMOS. When ...
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Electret condenser bias voltage
I have an electret condenser from PUI Audio (https://www.mouser.com/datasheet/2/334/AOM-5024L-HD-R-1219369.pdf). The Vs is recommended to be 3V but my circuit and only supply maximum of 2.5V.
The ...
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48 V phantom power backup: switch off the 9 V backup battery with FET
I found this device here on the site.
I need something to switch to a 9 V backup battery when there is a 48 V phantom power outage.
How can I change the FET to switch OFF the BAT1 (9 V) backup battery ...
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Transfer characteristics of a Toshiba DMOS FET
I am looking at the TBD62003A load driver, but it is very light on details about transfer characteristics.
Are there characteristics curves available from a similar device? Specifically, I want to ...
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Calculating CMOS threshold voltage
I found this solution in a textbook, and I do not understand how they calculated Vth2 (typo written as 'Vth' at the bottom).
More specifically, where does the 2Vm come from?
I understand that Ids1 = ...
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Possible FET with SMD marking 2YJ33
I need to replace a SOT-23 SMD transistor with the marking 2YJ33 (image attached Q1 and Q2). Any idea what it could be?
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0-10V LED driver dimming with Raspberry Pi and FET
I'm a beginner, so please be gentle!
I'm trying to dim the linked LED light fixture driver using a Raspberry Pi (RPi). I want to dim using PWM in conjunction with a FET. Before dimming I am trying to ...
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Is there a microscopic oscilloscope probe?
Does such a device exists to measure voltage and current in 14nm and below semiconductors?
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Mosfet Rdson inconsistency in datasheet? Or conceptual error?
I was checking the datasheet for the Allpower AP2012S and while checking the graphs to determine the Rdson in my point of operation I found what I think might be an inconsistency, however, I wanted to ...
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Controlling external device by tapping into existing transistor
I'm working on one project where I cannot figure out on how I can control my external device by tapping into some home appliance. Just to note, that I have very limited knowledge of electronics and I ...
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Help solve rds for pchannel FET from this datasheet
I would like to use a pchannel FET as a voltage controlled resistor in a circuit where my voltages are between 0 and 1.1 Volts. I'm hoping to use the J175 but truthfully I am having a difficult time ...
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Is it possible to make an OFET in a home lab?
Is there a way to build an OFET at home?
(low tech, no deep vacuum and plasma, without toxic/hard to dispose chemicals)
What can be the minimum budget for that?
While conductive polymers are pretty ...
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What is the best way to find an RF FET device for a design?
I'm searching for a jfet or mosfet for a receiver front end, but there doesn't seem to be many options. Everything I find seems to be obsolete. The closest thing I've found to a component that matches ...
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Picking a FET for Logic Level
I've always been confused when picking a FET to be used for logic level signals. There are so many factors to look at for FETs, I get overwhelmed.
In this case my supply voltage will be a 3 alkaline ...
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Which MOSFET should I use for high-voltage inverter circuit [closed]
I have an inverter circuit with 2 MOSFETs alternating, a capacitor, and a couple of resistors.
When I supply 5 V I can see a high-frequency square wave, given the capacitor and resistors values.
When ...
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FET: How to understand noise specification?
I was reading an article about electret microphones and there was a link to a datasheet of the FET which was used for impedance matching. It is a popular Fet which is used in many electret microphones....
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2N7000 N-Channel FET switch - resistor calculation for LEDs (design revision 2)
Follow up from a previous post about how to control a 5V supply to LEDs from a 3.3V logic GPIO on a Raspberry Pi Zero W.
Most responses recommended that I use a MOSFET / FET instead of a PN2222 ...
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Understanding the role of the FET in this opamp + Zener diode voltage regulator
I'm trying to repair my old audio CD player, and I've found a fault in or around this voltage regulator circuit (it's sourcing VCC for the DAC chip):
I understand how the Zener + opamp work to ...
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Mosfet power dissipation in this example
I am trying to design a buck regulator with the following specification:
Vin = 24V
Vout = 5V
I max = 8A
Fsw=300k. The load is basically a long strip of RGB LED's. Which in certain cases would be all ...
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Is a cylindrical GAAfet fabricated with lithography and etching?
The GAAfet, aka the surrounding gate transistor (SGT), is basically a FinFET that surrounds the channel on all 4 sides instead of 3. However, a lot of examples show a cylinder instead of a rectangle.
...
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How to use a MOSFET to switch up to its Vds rated specs (e.g. 100 or 150 V)?
So I'm still learning (old dusty ETE degree I finally got around to making use of lately), so be nice please. I get a ton of snark sometimes when I post a question on here. But then there's always one ...
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Are there robust through-hole MOSFETs for beginners?
I want to create switching circuits of less than 20mA in pos/neg 15V applications. 5 to 10 transistors, combination of N and P. Switching at 2.5kHz.
I simulated my circuits and now want to solder them ...
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DC Power Relay 12V inrush Current
I have a question regarding 12v dc relay circuit design.
About 350mA flows through the relay coil from the 12v power supply, so the pmosfet specification was selected as vds -30v, id -2A class.
The ...
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Control of External Power Source with Arduino
Please pardon my ignorance, I'm still trying to wrap my head around this problem. I have built a circuit that will allow me to control distribution of voltage from a single external power supply to ...
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Output voltage in a BS270 circuit
I am reading through Exploring Raspberry Pi and in a section on FETs, there is an example circuit. I understand how the controlled current is calculated $$I = \frac{V}R = (5V)(100\Omega) = 50mA)$$, ...
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BJT vs MOSFET switching speed
I've been reading various answers about the switching speed and frequency of BJTs and MOSFETs, yet I keep finding conflicting answers. Can anyone explain the discrepancy and the real answer? Sources ...
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Are there two sorts of *geometry* of JFET?
In some schematics of JFET, we see in the geometry that the source and drains are perpendicular to the position of the gate.
Example :
https://en.wikipedia.org/wiki/JFET
In some schematics of JFET, ...
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Where can I find the symbolic symbols of various bipolar, JFET, MOSFET in a *unified* style?
Where can I find the symbolic symbols of various bipolar, JFET, MOSFET in a unified style ?
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Why are there no P-channel SiC (silicon-carbide) FETs?
Looking at the top distributors, seems only N-channel power SiC are carried. Why is that?
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MOSFET to drive LED, never turns fully off
I have the following circuit (see attached) where I am using a SI2302 MOSFET to switch an LED using a micro-controller (internal pull down.)
The problem I am seeing:
Upon switching between 3.3V (HIGH)...
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