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)

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101 views

Over-discharge protection for 20V lithium battery pack

I am soliciting your help regarding a project I am working on. I have done my research but can't decide which solution is optimum for my needs. By optimum, in this case, I mean will consume the less, ...
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45 views

Why is the same MOSFET model give very different output for this circuit?

I have this MOSFET and as you see below it works fine when I try as inverting switch : But when I try this on breadboard with three 2N7000 only one of them is like the simulation. If I try with the ...
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73 views

Charge 12 V, 1.3 Ah lead acid battery via 12 V, 5 watt solar panel

Can someone explain me the below circuit which is used to charge 12 V 1.3 Ah lead acid battery via 12 V, 5 watt solar panel? The circuit is shown below I need to know what is happening in this ...
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191 views

Why PMOS act like “close switch” when zero voltage

in PMOS that Vtp less than 0 , from what I understand if We give Vg less than Vtp it has current flow from source to drain ,on the other hand if we give Vg more than Vtp it cut-off. but in digital ...
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95 views

How to build synchronous boost converter with IR2104 mosfet driver?

Does anyone know how to build a synchronous boost converter with IR2104 mosfet driver? I am a beginner and I have noooo ideaaa how to connect the circuit. The placement of inductor and capacitor ...
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46 views

Solid state switch with Terra-Ohm off-impedance

I am looking for a way to create an ultra-high impedance switch without mechanical components. The off-resistance should be around one Terra ohm for a signal range of 10V DC max. On the other hand, ...
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21 views

Switch bounce protection due to impact situations

I use a small form factor switch along with a PMOS as a power switch to a circuit. Due to form factor restraint, the switch available (and was chosen) are susceptible to a bounce problem during ...
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29 views

MOS and BJT, why the difference

It takes longer for a BJT device to come out of saturation than a MOS device to come out of triode region. It is explained by the base charge storage time, the charge has to recombine and go back to ...
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35 views

MOSFET current mirrors

so I am watching this lectures ( since the coranva virus , I am studying again electronics ). so at this lecture he is talking about MOSFET current mirros : https://www.youtube.com/watch?...
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40 views

What MOSFET parameters should I look into for this experiment?

I want to generate a low freq movement for this loud speaker coil by using a function generator sine output. With the function generator I can generate a sine wave between 0.2Hz up to 100Hz with ...
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19 views

Current Conveyor CCII internal circuital realization

I have read this article about current conveyor CCII, and I have some problems about understanding its circuital realization (page 4): The article says: The feedback of opamp structure [this ...
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88 views

What is the (exact) difference between CLM and DIBL in MOSFET?

I am wrapping my head around this for a bit and I understand both effects (Channel Length Modulation, Drain Induced Barrier Lowering). While CLM is usually explained as effective decrease of the ...
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79 views

What properties of MOSFET amplifiers made it so popular?

It seems to me that any circuit where the output voltage varies faster than the input voltage can be used to create an amplifier (for example a diode). We can bias the input voltage and use small ...
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22 views

Mosfet N and Vgs range

My schematic controls a Mosfet N gate by discharging capacitor voltage. It works, but when I calculated the min max, I've discovered that I'm a lucky man. Component : 2N7002 Vgs : Min =1 V / Typ : 2....
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51 views

Half bridge Gate Driver UVLO

I am interested in designing a BLDC motor driver capable of operating at low supply voltages and relatively high currents (i.e. a device capable of operating with a 3V minimum supply and a phase ...
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29 views

Mosfet VNK 37 replacement

Does anyone can help me find a Mosfet VNK 37? I habe bose soundtouch 30 and it wont turn on,i have my friend open it and he said i need to replace 1 component mosfet vnk 37. Or if i cant find the ...
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47 views

Suitable MOSFET for my application

I need to control 12 small 12V vacuum pumps with 3.3V coming from a STM32 microcontroller. Those vacuum pumps don't draw more than ~1.5A. My idea is to use MOSFETs but I'm having a hard time choosing. ...
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79 views

High frequency switching MOSFET

i'm having af hard time finding the proper MOSFET for my wireless power transfer. I need a MOSFET which can easily do 100kHz without overheating and with minimal power dissipation. I'm currently using ...
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74 views

Current mirrors inside an OTA (Operational Transconductance Amplifier)

let's consider this transconductance amplifier (OTA) (reference): I have a very basic question. Why do wee need the mirrors M5,M6,M7,M8,M10? Why is the output taken from that current source? Why ...
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46 views

MOSFET switch for inverter

I need to control my el wire from Arduino Lilypad. I am going to use MOSFET switch circuit. El wire is ran from 9V battery and inverter circuit. Inverter is using about 90mA current. Lilypad has 3.3V ...
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70 views

Sensor 30 meters away

for my home automation project i'm using 10 Sensirion SHT21 Temperature and Humidity devices, those devices are distant 30/50 meters away from my ESP32. Those devices are driven using 5V and at both ...
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58 views

How to design a mosfet relay switch

I'm new to KiCad and PCB design and I'd like to consult on how to build a switch based on relay and MosFET using an STM micro-controller. My initial design is this: and I'd like to know the basic ...
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77 views

Circuit to connect/disconnect a battery from circuit input, controlled by the MCU, self-power-off

Here is my current idea, but I'm wanting something better. Because in my circuit it is missing a way to discharge the capacitor C1 whenever the battery is disconnected from the circuit input. I have ...
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30 views

Cascode current mirror output dynamic range

let's consider this cascode current mirror (Microelectronic Circuits, by Sedra Smith): The books says its best advantage is the high output resistances, which is amplified by the presence of Q3. ...
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2answers
122 views

Logic Level Converter for Negative Voltages

Here is logic level converter mostly used for converting signals between 3.3V and 5V. (Other positive levels such as 1.8V are also possible). What if I want to convert from 3.3V to -5V logic (negative!...
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72 views

How does doping concentration affect MOSFET switching speed?

I've read that increasing the doping concentration would cause the carrier mobility to decrease, but at the same time, it would lower the threshold voltage. So a few questions come to mind: When we'...
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52 views

How to amplify signal for driving a more powerful motor

I have a 0-12V signal supplying max. 10A, which drives the 12V DC motor with peak consumption of 10A. I'd like to replace this motor with a more powerful 12V DC motor with the peak consumption of 30A. ...
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42 views

LDO transient performance enhancement circuit understanding

For the following LDO circuit, how does the transient performance enhancement circuit sub-block in green color works ?
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110 views

Can I use a p channel mosfet as reverse polarity protection but still charge a Li-Ion battery?

I want to design the following reverse protection circuit: The gist of the design is that I want to run a SIM808 chip from a 3.7V battery. I understand that the circuit as such will protect if the ...
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98 views

MOSFET small signal model output resistance

I am wondering what is the output resistance of the circuit below. I found that it depends on the gate voltage: $$ \begin{aligned} R_{out} &= \frac{V_{out}}{I_{out}} \end{aligned} $$ $$ \begin{...
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103 views

Alternative for THT component with SMT

Am working on an arduino project where am controlling a motor through a I/O pin turning it ON and OFF, circuit below: Now am trying to make a PCB out of this circuit, to do so i wanted to switch ...
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32 views

Single Input Transconductors Implementations in IC

In my lecture notes I have these following configurations for realizing single input transconductors in integrated circuits: I have the following questions: Consider the first circuit: the drain ...
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SIZING steps and Interpreting Mosfet datasheet

After reading those Interpreting Maximum Power of a MOSFET from the datasheet How to interpret Vgs(th) min/max in a MOSFET datasheet? https://www.infineon.com/dgdl/Infineon-...
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139 views

P-Channel Mosfet switch and Capacitor Discharge on Drain

I'm using the following circuit with a P-channel mosfet to switch the positive line to a transceiver. I want to keep the transceiver grounded and switch it off to stop current draw from the battery. ...
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68 views

Mosfet control Rds on , and Vgs

I want to know how to calculate Vgs , assuming load current Id is constant , Vd = voltage of battery is constant , and fet is operating in thermal stability region , so there is no thermal runnawy , ...
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79 views

Reverse Polarity in rush Protection 2 p fet parallel

after reading those links : Reverse-polarity protection P-channel MOSFET Optimal method for multiple MOSFETs for LED driving with a shared power rail Parallel MOSFETs and this pdf : ...
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109 views

Diode Connected MOS

let's consider the equivalent circuit of a diode connected Mosfet. Since the current source between drain and source is: gm * Vgs = gm * Vds and it is proportional to Vds, it means that this ...
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41 views

Power zener with mosfet + zener

I have two solar panels in series giving ~106 volts when open circuit and around 4 Amps when loaded. My mppt controller could accept 150v on the input, but it blew up when the battery was ...
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47 views

Current Sink with OP184

I got a question. I'm building a current sink for a project and below you can see what i came up with. I modified the Linear Tech. circuit (LT1492) because i wanted to have lower Vos. I also added 3 ...
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41 views

SIPMOS as current source

I read this question and I have the same issue: acquire and protect an input with 5-24V range. I wonder if nowadays I can use a BSS126 as current source transistor. It's a depletion mode N-channel, I ...
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73 views

Unwanted mosfet turn on and irregular duty cycle when driving with IR2110 how to fix?

I am designing an MPPT charge controller and testing all the different components. At the time of writing I am testing the buck converter. During testing, I used a 10 ohm load instead of the battery ...
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76 views

MOSFET Common-drain amplifier configurations

In my text-book is shown this circuit for Common-Drain Doing practice, I found this exercise What does it change between these two configurations? Voltage gain, input and output resistances, lower ...
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83 views

What is wrong with the MOSFET IRF540N ? Even with the zero gate voltage, why current is still flowing through drain to source?

Actually I was developing the overcurrent protection using op amp LM-358 as described in the second picture . I made the circuit as described on this link https://circuitdigest.com/electronic-circuits/...
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42 views

Strange MOSFET Common-Source with RD=0

I was trying to solve this circuit(find the Q Point, voltage gain, input and output resistances in midband region, the lower cutoff frequency using SCTC method), but I was confused by the absence of ...
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62 views

USB cut off with N-MOSFET

I would like to use a N type mosfet in order to cut the current from a USB charger. The mosfet reference that I currently have is an IRLB8721. I have already done a similary thing to another project ...
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47 views

the transconductance of cascade MOSFET IF channel length modulation is NOT ZERO

What would the derivation of the cascode MOSFET transconductance in small signal analysis IF THE CHANNEL LENGTH MODULATION IS NOT ZERO, as most examples for the cascode mosfet transconductance say in ...
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55 views

How to project a FET transistor as an amplifier?

I am trying to solve a problem on using an FET transistor as an amplifier with the common source configuration. The model should be appropriate for high frequencies. The problem gives the equivalent ...
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60 views

Doubts about a differential negative resistance oscillator

let's consider this kind of differential negative resistance oscillator: The output of this circuit is VA - VB. My book says the following sentence: From a quick analysis of the circuit it can be ...
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43 views

Subtleties of Boost Conver (Step-up Converter)

simulate this circuit – Schematic created using CircuitLab Generally Boost Converter fault happens in my workplace and difficult to find the problem of converter. So I try to understand the ...
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72 views

EveryCircuit mosfet specs?

Has anyone ever used the circuit simulation 'EveryCircuit'? I bought an android license for it back in 2012 and used it quite a bit for simple circuit tests prior to building something as a lay ...

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