A n-channel metal-oxide semiconductor (nMOS) transistor has n-type carriers in the channel. A positive voltage on the gate turns inverts the substrate (PWell) creating the channel and turning the device on. The term may also be used to describe logic circuits built around nMOS transistors.

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Voltages to keep my circuit running at 200mA with NMOSFETS

Im trying to build a circuit to send information using IR led, using pulse signals my leds (TSAL6400) operates at 1.35V, and their maximum pulse current is rated 200mA After struggling a bit with ...
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103 views

3-pin MOSFET: P or N type?

This may be a silly one but I couldn't seem to find an explicit answer: with a 3-pin MOSFET, how do I determine whether it's an NMOS or PMOS? I'm making some assumptions here: I've already found ...
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2answers
60 views

Need gate driver for MOSFET (IRF540) and microcontroller

I'm trying to use a STM32F100RBT6B microcontroller to turn on a n-channel MOSFET (IRF540) to switch on a voltage of 24V to an electrical magnet. I understand I would need a gate driver between the ...
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50 views

microelecectronics doubt [closed]

I was going through Sedra and Smith (6th edition) and had a doubt. In example 4.11 (page-405), how do we know in a question if we have to join G and S terminals and there will be a current flowing ...
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37 views

Multistage CMOS amplifier design

my professor gave us a task to design a multistage amplifier using NMOS and PMOS transistors with a minimum width W=18um, 1.8v battery(multiple if needed and any sort of resistor/capacitor. The only ...
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42 views

Basic Nmos amplifier working

I am trying to understand this circuit here. I do not understand clearly how this works. I know that the PMOS is a current source but what impact does the resistor Rb have on this ? Could anyone ...
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49 views

Trying to simulate the linear region of a MOSFET

I wanted to simulate the linear region, so I tried this: simulate this circuit – Schematic created using CircuitLab I expected the triangle wave to be curved, but it didn't have those ...
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2answers
39 views

Can a NMOS transistor be used as a Current Controlled Voltage Source?

Assuming an NMOS transistor is in saturation. Can you apply a current \$I_{DS}\$, resulting in an output gate-source voltage (\$V_{GS}\$)?
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123 views

NMOS - Why is a resistor necessary?

I understand how the logic levels of an NMOS work with a pull-up resistor. 1. What would happen though if there was no resistor attached? (What would the logic levels look like and why?) 2. What ...
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50 views

Depletion Mosfet working as enhancement NMOS

The depletion mosfet can also operate in enhancement mode when the gate voltage is positive (say for depletion type NMOS). My question is : Will the Shockley equation be still valid in the ...
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1answer
76 views

Bias common source diode connected load

To amplify small signal we need to bias M1 and M2 in saturation mode. Obviously, M2 is always in saturation because Vgd = 0. However, how should I bias M1 in saturation?
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56 views

Biasing an NMOS to get rid of \$V_{th}\$

So here's a common way of cancelling out the \$V_{th}\$ in an NMOS. Am I better of use a good quality zener (in series with a resistor) or stick with voltage divider R1 and R2 below. Assuming we can ...
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104 views

MOSFET shorted after I connect them in parallel, what's wrong?

One of my MOSFET source-drain shorted after I connect them in parallel? So I was making an ARC speaker yesterday, and I used one MOSFET ( irf540), and it got really hot, but it did not blow up, so I ...
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4answers
130 views

SOT-23 NMOS transistor power dissipation

I am working on a design of a control system that controls a few small solenoids, each drawing about 200 mA of current and operating at 15-18 V. These solenoids are activated by NMOS transistors. Due ...
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91 views

Simple NMOS transistor circuit output impedance

I am having trouble figuring out the best way to determine the output impedance of this simple NMOS transistor circuit: Both transistors are equal, and the body effect is ignored. What method ...
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2answers
279 views

CMOS: Why is an nMOS transistor a bad conductor of high logic, but a good conductor of low?

I can't find an answer that addresses this and makes sense to me. I know that V_t is subtracted from the 'output', but I don't understand why.
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56 views

Gate voltage and drain current relation

I am new to electronics and have the following doubt. Say Vgs= 3V to a NMOS produces Id= 3A. Now if we place a 3A current source at the drain,will it cause a 3V at the gate, when the gate is open ...
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1answer
58 views

High Drain Current MOSFET vs Low Drain Current MOSFET for Synchronous Buck Converter

For a battery charging application, i have to build a synchronous buck converter (i/p voltage = 12V , o/p Voltage = 4.5V) which would be driven by a PWM signal from the micro-controller. This Buck ...
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1answer
82 views

Tristate logic equivalent in NMOS logic

Suppose I have 3 signals generated by NMOS logic. Each of those signals has an associated enable pin that when driven high will result in the value of the signal appearing on the output (I should note ...
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83 views

Pull up resistor in NMOS logic value

For my senior high school project I decided to build a basic CPU from discrete components. I plan on using a 5V logic level and the current design calls for around 2000-3000 N-channel MOSFET ...
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41 views

Capacitor problem using an NMOS inverter with depletion load

When Vin is low the enhancement type NMOS is off. That means the drain current of both transistor is zero, isn't it? If it is, then how will the parasitic capacitor charge? I'm not understanding! ...
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2answers
351 views

Why is CMOS fall time faster than rise time?

I've just started a computer architecture class, and the slides from a lecture says that the reason why fall time is faster than rise time is that the NMOS electrons have more mobility than PMOS which ...
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23 views

PMOS bulk voltage affect NMOS V_t

I am using a MOSFET in a IC (CD4007), only the NMOS in the IC. Then, I want to know the parameters, \$ k_n\$, \$W\$, \$L\$ and \$ V_t \$, for this, I using a method for characterize the NMOS. The ...
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305 views

NMOS and PMOS current sources

I'm really confused with the representation of PMOS device shown in the figure. Since conventional current direction in PMOS is from source to drain, shouldn't the current source be pointing ...
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156 views

Single MOSFET Amplifiers

Why is it that when I see single MOSFET amplifiers or even complementary ones (one NMOS and PMOS), they would use what in single BJT amplifiers would be called "Common Emitter Amplifier". The output ...
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42 views

Enhancement type nmos threshold voltage

in an enhancement type nmos when a channel is created then a depletion layer should be created under the n-channel which means electrons get a potential barrier to overcome.now is this potential ...
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76 views

Finding 2nd Vds value in a NMOS circuit

I think for the first part of this problem I solved for Ra = 13kohm and Rb = 7kohm, but I'm not able to understand or see how to get the voltage at the point V1. Any idea on how to go about finding ...
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Depletion NMOS that's saturated at 0V

May seem like a weird request for a part, but are there any Depletion NMOS out there that is already saturated when you apply 0V to gate or if the gate is not connected?
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183 views

Help with MOSFET buck converter

I've started learning about Buck Converters, and I made a miniature one on an Arduino prototype shield. But when I turn the thing on, the voltage is stuck at 5v (the voltage input). I tried ...
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104 views

NMOS open drain output vs PMOS open drain output

I'm reading HT1632C LED driver datasheet and it has on the first page in the features section: Selectable NMOS open drain output driver and PMOS open drain output driver for commons Does it ...
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67 views

what would the drain voltage be if NMOS source voltage is not ground?

Hi I'm a beginner trying to learn CMOS cuicuit. Let's say we have two NMOS connected as shown. Given: A, B, C are connected to Vdd = 5V; VtM1 = 0.6V is the threshold voltage of M1; VtM2 = 0.5V ...
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1answer
51 views

NMOS saturation mode: why is there no channel?

I have a question about the saturation mode. The cross-section of an NMOS transistor in saturation mode is usually drawn like this: But it seems to me that there can be no current from source to ...
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34 views

NMOS amplifier simple question?

While studying the NMOS amplifiers in my book I came across operations with differential output voltages and this circuit specifically.I want to understand what are the drain voltages and what is the ...
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243 views

How to find the Q point of the NMOS transistor in Voltage-Divider Biasing Circuit?

The following is the circuit needed to be analyzed to find the Q point(\$V_{GS_Q}, V_{DS_Q}, I_{D_Q}\$). \$V_{TN}=1\text{V}\$ \$K_n=0.5\text{mAV}^{-2}\$ simulate this circuit – Schematic ...
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1answer
40 views

Help with NMOS Gate question

In this picture, when v1 and v2 are 0, M1,M2 are on and M3,M4 are off. V_T(threshold) = 1.7V, V_DD = 5V. Why is it that M1 and M2 are ON under these conditions? I thought when there is no power ...
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201 views

DC analysis of common source MOSFET circuits to find gate voltage using different power supplies

simulate this circuit – Schematic created using CircuitLab strong text I am solving problems on DC analysis of MOSFET circuits. We are supposed to find various parameters like Id(Drain ...
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54 views

NMOS Channel Type

I've seen some conflicting information about the inversion channel for an NMOS device. Is NMOS n-channel or p-channel? And is the substrate n or p? I know PMOS is just the opposite for both and the ...
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2answers
782 views

Create a CMOS circuit from a logic function [duplicate]

I have to create a CMOS circuit from the logic function: F= ~A + B (notA or B). I made the truth table but I'm stuck here trying to make the CMOS circuit. Any ideas anyone? Thanks! I know it's the ...
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1answer
174 views

CMOS technology, use a NMOS or PMOS as series switch?

A general question regarding switches in CMOS. Have a look at the schematic below (symplified current mirror) There is a input reference current, on/off switch, a PMOS mirror and the resulting ...
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75 views

Stable solution

To my understanding a stable solution for a transistors is when the voltage will not fluctuate due to to a change in Vin or something like that. My question I guess would be, where would I start ...
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1answer
87 views

Why feedback is activating at more than 4V?

In this circuit: I don't get why the current start flowing from more than 4V. I thought was due to threshold, but the same happens with an NPN as M2 or using an BS170. With this last one, ...
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2answers
87 views

Trying to find steady state

I'm taking my first course in electronic circuits and I'm a little lost when it comes to combining NMOS transistors with capacitors. In particular I am having trouble with finding the steady state for ...
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1answer
155 views

Source potential for MOSFET with grounded substrate

Considering the configuration below, the source's potential should be invariant with respect to Vg (as long as Vg>Vt). So Vs is equal to Vdd. But if the substrate is connected to the source, as ...
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How can PMOS eliminate body effect but NMOS doesn't?

I have a question on the body effect of MOS transistor. In particular, how does the body effect in PMOS be eliminated (by connecting bulk to source together) while this similar technique doesn't do ...
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1answer
390 views

NMOS transistor: how does its structure relate to two interconnecting diode?

There is a popular idea that structure of NMOS transistor could be viewed as the inter-connecting diode across their PN junction. Therefore, when operating NMOS, you always want to keep the Source and ...
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0answers
72 views

Preference of MOS resistor as load in MOS inverter [closed]

Whys is a MOS resistor preferred over diffused resistor as load in design of a MOS inverter?
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66 views

Find Id of NMOS

I need to find the drain current in the above circuit where I also know \$V_{TH} = 1\,\mathrm{V}\$ and \$\mu_{n}C_{ox} = 2\cdot 10^{-4} \frac{\mathrm{A}}{\mathrm{V}^2}\$. I'm just not sure about ...
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262 views

NMOS: what exactly forms the inversion layer

I have a a question on forming of the inversion layer in NMOS. More specifically, please refer to the following figures The negative ions (in-mobile) are due to the the accumulation of the positive ...
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279 views

NMOS: why VGS instead of VG?

I am having lots of trouble trying to understand how the mosfet is triggered. The text I read assumes the source of the NMOS connect to ground, while a positive voltage is applied at the gate. ...
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533 views

Charge Pump for driving NMOS

I was looking for a way to drive the gate of a power NMOS. Since I've already have a small FPGA available at a independent backup-3V3 rail, I was thinking I could use it's internal oscillator to build ...