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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6
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1answer
41 views

MOSFET power dissipation calculations - Diodes Inc. datasheets

Looking at Diodes Inc. datasheets, I am having trouble following their power dissipation limit calculations for their MOSFETS. E.g. for DMG4496SSS http://www.diodes.com/_files/datasheets/ds32048.pdf ...
1
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1answer
37 views

Current flow in long channel MOSFET in saturation

Why doesn't the current in long channel nMOS decrease with drain voltage due to pinch off that takes place when gate voltage at a point in the channel is less than the threshold.
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2answers
43 views

Basic gain cell

Guys i was going through basic gain cell topic in my textbook. I came accross this circuit. Pls explain how vo is not equal to VDD. I mean how can they be different? There is no resistance that ...
0
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0answers
25 views

Proper way of connecting logic and power GND on IR21844 mosfet driver

I am tring to build half bridge using IR21844 mosfet driver, i have read datasheet and design tips and some of the topics in this forum. The one thing i still cannot get is the separate GND pins ...
-4
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0answers
24 views

A mathematical expression for finding Impedance of MOS diode [on hold]

I need the mathematical expression for impedance of a MOS diode looking into its source so that I can calculate it for my circuit.
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2answers
54 views

what is conduction loss in a transistor(BJT)? how is transistor's conduction loss lesser than that in a mosfet?

why does a MOSFET have higher conduction loss compared to a transistor? While designing switching circuits , driver circuits controlled by a microcontroller, how should i select a switching ...
0
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1answer
55 views

What is the methology of sending signals via Bi-Direcional MOSFET?

I am trying to make a simulation by using Multisum 14 for i bi-directional channel for Logic level circuit from SparkFun which use Philips AN97055 IC as a Bi-directional level shifter... My circuit ...
0
votes
1answer
32 views

Biasing using constant current source

guys i was going through this diagram in my book when these lines came along(i am a student): Here RG(usually in M-ohm range) establishes a dc ground at the gate and presents a large resistance to ...
-1
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0answers
35 views

MOSFET Heatsink Question

This is a follow up to my question from yesterday MOSFET Heat dissipation question Now that I know I need to use heatsinks on my MOSFETs, I've been looking around trying to find some. I found these ...
0
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1answer
120 views

Lower current through different transistors

I'm building a small PIR driven circuit, currently a simple PIR activated light, and for this I'm using an RGB LED strip as I had it lying around from another project. The diagram that follows works ...
1
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2answers
66 views

MOSFET Heat dissipation question

I'm designing an RGB LED strip driver, and for the MOSFETS for the PWM power switching I'm looking at using the PSMN022-30PL. It has a voltage limit of 30v, and can supply up to 30amps, which is more ...
0
votes
3answers
129 views

Ultra low power 555 timer circuit

I am trying to design a circuit involving an LMC555 CMOS timer operating as a monostable multivibrator. Essentially, I want a momentary switch to turn on a set of LEDs for ~20 seconds and then turn ...
0
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0answers
50 views

Vds Voltage of Nmos transistor at Lineer Region

I know the conditions for mosfet Id equations in saturation, linear or cutoff mode. For this circut, how can we find the Vds voltage when we know only values of the resistors and Vdd at linear mode? ...
0
votes
2answers
70 views

Gain and output impedance of an amplifier

I am trying to understand the physical phenomenon that leads to increase in gain of an amplifier as the output impedance increases. When we have resistive loads in a single stage amplifier, they ...
1
vote
4answers
105 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 ...
1
vote
1answer
50 views

MOSFET output I on Arduino

I am trying to power a pair of TEC (thermo-electric cooler) using Arduino. I came across this guide that is used to power one. Because I have two, I want to know if I can still use something such ...
0
votes
1answer
71 views

How to calculate Vout from the MOSFET circuit

This circuit diagram is given in my book : simulate this circuit – Schematic created using CircuitLab and said that from the above figure , they calculate \$ \frac{V_{out}}{V_p} \$ ...
0
votes
2answers
84 views

Do I really need an H-Bridge controller in this application?

I'm looking to integrate a latching solenoid in my next project. I found a 5V latching type here: LHLA0531111H The manufacturer recommends I use an H-bridge to control switching of the solenoid. ...
0
votes
2answers
67 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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votes
0answers
32 views

Leakage current variation with decrease in threshold voltage

As MOSFETS scale down and follow Moore's "Law." The voltages used on the MOSFETS also scale down. Do these newer, smaller transistors used in digital circuits have more leakage current do to ...
0
votes
1answer
67 views

P channel mosfet battery charging/power selection circuit help

I am a hobbyist and new to this, but I am not sure if my circuit it right. The goal is: To power the rest of the circuit from a DC source, a USB, or a battery, in that order. When there is no DC or ...
4
votes
2answers
106 views

Buck Converting Voltage, to Switch Original Voltage

I'm learning electronics, so I want to sanity check this approach in case I'm missing something. I have an arduino (at 5V) controlling power to a set of lights at 12V, via a mosfet. This is all fine, ...
1
vote
1answer
88 views

Using optocoupler with MOSFET for dimming a LED

I have a blue LED which I want to dim using an Arduino, an optocoupler and an N-MOSFET. For achieving this I assembled the circuit on a breadboard as shown in the pictures, using a YwRobot breadboard ...
1
vote
1answer
50 views

Bipolar Square Wave Generator

The design requirement is to generate a +/-12V square wave from a 0-3.3V square wave at 1kHz. Here is what I came up with: PILOT_CTL is the 0-3.3V square wave and the end of R6 should be the ...
0
votes
1answer
63 views

Desoldering a TO-220 MOSFET from a plated through-hole board with SMD complications

I'm planning on replacing a TO-220F package MOSFET on a through-hole circuit board that also has SMD components on it. In this case, an SMD capacitor is connected to the source gate of the MOSFET by ...
1
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2answers
70 views

Mosfet H-Bridge Design Question

I have a few questions regarding an H-Bridge design that I like. I am having a little hard time understanding some parts of it. So this is the design that I found online here. I changed the motor ...
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1answer
62 views

what is this error in PSPICE with IR2113

I want drive a buck converter with bootstrap technique. but this circuit does not work!
0
votes
1answer
59 views

Is it possible to use a MOSFET for Li-ion reverse polarity protection when protecting a charger?

I've made a simple charger out of 4 TP4056 modules and 4 18650 sockets. These modules have overcharge, undercharge and overcurrent protection included, but I also want to know how simple it would be ...
2
votes
3answers
58 views

Boost converter for high side Mosfet

I recently came across an article explaining how to drive a high side MOSFET using a "separate isolated power supply whose ground and the ground of the MOSFET-based circuit are isolated". However ...
3
votes
5answers
217 views

Using MOSFET as switch

I am new here so I apologize in advance for any mistakes in the way I am going about this. I had a question regarding a project that I am working on. I am trying to use a MOSFET as a switch that I ...
2
votes
1answer
81 views

Creating a robust power MOSFET switch

So I have been researching about protecting a MOSFET. I have used MOSFETs for basic on/off switches but never really thought about fully protecting them. I have used them for on/off switches to engage ...
1
vote
1answer
42 views

Pulse Low on High Signal

I am trying to build a circuit that disconnects the output for a brief time when power is connected. However I want the circuit to remain connected after power is removed. I can achieve the first ...
1
vote
1answer
48 views

Class AB Amplifier Frequency Response

I have designed an AB Audio Amplifier, but even though the gain is acceptable, the frequency response is terrible.As seen in the schematic, there is a feedback/preamplifer stage and an output stage, I ...
0
votes
1answer
62 views

DC/DC Converter Instant Off

The output voltage of my DC/DC converter and my power supply both slowly descend. I believe this is due to capacitors being close to the output of each device. I want to get an instantaneous, or as ...
1
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2answers
288 views

TL431 Low battery cut-off

Good morning Could somebody please explain the operation of the attached diagram to me? The circuit was proposed here and here as a low voltage cut-off circuit, which switches off the MOSFET when ...
2
votes
3answers
106 views

MOSFET gets unusually hot in a SEPIC converter

I have constructed a SEPIC converter which is to be used for maximum power point tracking (MPPT). For simplicity, I am currently just using the hill climbing algorithm with fixed duty cycle steps of ...
1
vote
1answer
80 views

Automatic Power Selection Circuit

I am trying to build a circuit with 2 inputs and 1 output using Mosfets. I will try to explain what I want.. The circuit should accepts 2 input DC voltages , the first input voltage called ...
-2
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1answer
81 views

What is the most commonly used transistor?

Just a question about transistors from a rookie. I was wondering what kind of transistor is most commonly used? Bipolar transistors? JFET? MOSFET?
0
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2answers
34 views

A dual-input solid-state switch that will reliably work in a car

I need a switch, but with a small twist. If it was operating on normal filtered DC I would know how to make one myself. But since it's for a car, I need help designing it for reliability and surge ...
0
votes
1answer
27 views

A small signal NMOS transistor

I am reading an application note entitled Using MOSFETs in Load Switch Applications This part says that Q1 is a small signal NMOS transistor. Could you explain what does it mean by "small signal ...
0
votes
1answer
61 views

H-Bridge driver circuit design

I have built the following H-bridge driver circuit (The red resistors R9 and R10 were not included). However during testing I have found that I am constantly blowing the high side P-Channel MOSFETS ...
0
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1answer
83 views

Finding output resistance

I am confused on how to find the output resistance of transistor amplifiers in general, but more specifically when it's a combination of different resistances. Here's an example (concrete) of the ...
0
votes
1answer
47 views

Driving MOSFET with load on source

I would like to know what circuitry I will need in order to drive a N-Channel MOSFET (IRF1405) with the load placed on the source. From my understanding the laod is placed on the drain however I ...
0
votes
1answer
71 views

P-chanel MOSFET series configuration

Good day I'm busy designing a small DC UPS to run some appliances when the power goes out. I am, however, having trouble with an element in the battery switch-over circuit. I decided on using a ...
0
votes
2answers
59 views

switch for AC voltage

I am designing a switch for AC circuit. E.g. when I apply a small DC voltage, AC current is allowed to conduct, otherwise there is huge resitance stop the current from flowing. I found 2 possible ...
0
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0answers
31 views

MOSFET usage in LTC1153

I am trying to simulate the LTC1153 in LTSpice. I am using the MOSFET - IRLHS6376PbF -Datasheet.. The circuit is as shown - . The output at gate pin is almost 27V. Now, the max Vgs of the MOSFET ...
0
votes
1answer
97 views

Using a Mosfet Gate driver to directly drive a small stepper motor?

I need to control some small, low current stepper motors from a 3V ARM micro controller. The motors typically require 5-12V at 400mA (30 ohm 41mH windings). What occurred to me is to use a Mosfet ...
0
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1answer
112 views

Can you drive a motor bidirectionaly with just N channel mosfets?

I bought a bunch of IRFZ44Ns from China in the hopes of driving a motor bidirectionaly controls from and Arduino, but now I realise that a full bridge requires both P and N channel mosfets.. Is it ...
0
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0answers
33 views

Where does this effective field come from? Semiconductors

I'm having trouble with this question. I've had a look around but I can't seem to find the answer. Any ideas? Is this something that is specific to each graph or is it just always one of the ...
3
votes
2answers
69 views

How can I adapt a 3-pin PC fan connector to a 4-pin connector?

My computer's motherboard uses all four pin fan connectors with no support for speed controlling the older three pin fan connector. The problem is, all the PC fans that I have use a three pin ...