Tagged Questions

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)

60 views

Why are my LED weak?

I am beginner enthusiast. I was trying to make lights under my bed by following this tutorial: http://aruljohn.com/blog/raspberrypi-christmas-lights-rgb-led/ It worked for me with a 1 meter color ...
44 views

Sedra & Smith Microelectronics 7th edition Problem 7.8

The answer is 0.712V, but how?
43 views

MOSFET Drain Voltage

I am trying to simulate a single NMOS, I calculate the I_ds but I need the voltage of the drain terminal. Should I multiply the I_ds value by a resistance value? Is this resistance constant? If not ...
30 views

Relay vs Switching Voltage Regulator

I have a microcontroller Atmega328p and some sensors like Dht22,Lm35,switching voltage regulator and a 9V battery.When my microcontroller is on sleep the total circuit consumption is about 11mA.That i ...
18 views

Arduino Uno, HC-06 Bluetooth & RGB LED Strip on the same 9V Power source

Hello! I am a complete amateur when it comes to electronics so forgive me for any misconceptions. I am trying to design a circuit that will power an RGB LED Strip (here depicted by a single RGB LED)...
54 views

Searching for exotic SOT23 P-channel mosfet where source drain swapped

Due to an error in the layouting process a batch of PCBs has to be scrapped. Instead of the standard pin assignments: 1 - Gate 2 - Source 3 - Drain we used: 1 - Gate 2 - Drain 3 - Source As a ...
37 views

MOSFETs as Switches

How could you use a MOSFET as a switch to drive a motor of 12-40V and 240W? As well as would it be able to operate at high temperatures (about 150degC)?
88 views

Transistor PWM Generator (No ICs) for practical application

I want to produce a good quality PWM signal with transistors(BJTs, FETS, etc..). I do not want to use an IC at all(learning to use transistors properly). I'm currently using a BJT Astable Mutivibrator ...
20 views

How to switch on/off 8mm(1w)led connected in series? [on hold]

I have 8mm led connected in series(50 nos) where each led take upto 1w . I need blink the led for 3sec once . I need a application to be done like this I did this by using 555 timer ic and using ...
51 views

Power Dissipation of Power Mosfet

I am doing power dissipation of a power mosfet. My design requirements are :- 20A @ 12-20V (Ambient temp will be around 50 deg Celsius) The mosfet I am using is :- http://aosmd.com/res/...
136 views

Cheapest Raspberrypi (or MCU) on/off power supply latching issues

Together with a friend we tried to implement the following schematic we found online after a quick search for "simple raspberry pi on/off latch power supply": Then we simulated the above schematic ...
39 views

How to calculate the dead time to incorporate in the complementay PWM input to an H-Bridge designed using MOSFETs?

I am working on making an autonomous robot. Right now, I am involved in designing an H-Bridge using discrete components for my robot. I am almost done with the H-Bridge design, and want to test it ...
78 views

Why do I get maximum output from OpAmp

I adapted a circuit for a voltage controlled isolated resistor using a LM324 OpAmp, a Darlington NPN (MPSA14), and a Fairchild Opto-FET (H11F1). The mission is to provide a 0 - 10K isolated ...
81 views

Multiple fingers vs single finger layout (MOSFET transistor)

Please, provide a summary of advantages and disadvantages of a transistor layout with multiple fingers (MF) vs single finger? When laying out a MOSFET with a particular width and length, in an EDA ...
44 views

MOSFET connection within oscillating circuit

I'm working on a group project, where for one part of the circuitry we have a "Royer Oscillator", which can be turned on/off via an N-channel MOSFET (IRFU4105ZPBF) at the input (whose gate is ...
59 views

what is critical in handling Heat dissipation of mosfet - Source or Drain!

I am working on a board which is connected to a DC power source of 12V/20A. To control the power to the load , I am using a PMOS as high side switch as shown below :- My Doubt is, from power ...
33 views

microcontroller suggestion [closed]

my requirement is 2 on/of buttons 3 buttons use for 3 steps of motor speed control High medium and low. and they also remote control please suggest a microcontroller which is suitable and low ...
47 views

Applications of transistor feedback

I saw the following circuit in an electronics exam. I think the feedback network consists of a transistor (M3) and a resistor (Rf) and the feedback type is current-current; Is this analysis correct? ...
26 views

Recommend MOSFET For PWM Operation [closed]

I am looking for a N-MOSFET for fast Switching( PWM ) to control the speed of 5V DC Motor. I will be providing a Voltage of 5V (Voltage to be provided to DC Motor) at the Drain, and connect Ground at ...
57 views

hybrid-π model VS T-Model for MOSFET and BJT

1) when to use T model for MOSFETs instead of hybrid-π model? 2) when to use T model for BJT's instead of hybrid-π model?
44 views

Class D Output Stage - MOSFET turn off diode

I am currently working on a class D audio amplifier. During this process I've come to have a pretty decent prototype, which I now wish to improve. In this manner I wish to improve especially the ...
117 views

Is the 555 necessary here, or can I just use an op-amp?

Context: The circuit's main input is a line-level audio signal from a computer. Every time that something loud happens in the audio, I need the solenoid to activate for about 100 ms. The first ...
34 views

In MOSFETs why is the gate-body inversion layer voltage able to create a conducting channel, yet the same source-drain voltage not?

I have very little experience with electrical engineering, so please bear with me. I was hoping to get a qualitative explanation as well as pointers to the maths/formulas which could formally explain ...
867 views

I was explaining a transistor to someone, and I realized: I don't really understand several key concepts at a low level. Help?

(Surplus story removed.) I was explaining MOSFETs, CMOS, and logic gates to someone and realized I didn't grasp some concepts as well as I thought. It culminated when he drew a single transistor, ...
20 views

How to use BSIM3v3 capacitance for hand calculation?

As you all probably know, capacitances in BSIM3v3 are just the partial derivatives of the terminal charges with respect to the terminal voltages. They are not physical two terminal capacitors. Cij = ...
42 views

My nMOSFET (maybe non existent). N canal with Vgs=0?

if I realize the following nMOSFET: is it possible to obtain n canal with $V_{GS}=0$? Thank you for your time.
67 views

Is this circuit possible? using same pins for active low/high

I designed this circuit : The goal is to use A B C ports on a pcb, to perform as: output- active low/high, or as an input. (not in the same time) All Fets are <...
75 views

Why is there a resistor in a cmos X-OR gate?

While reading up on logic gates i came across this image on Wikipedia: According to the article, the resistor on the supply voltage for the inverter is necessary to ensure that no current is leaked ...
71 views

Why L6743D MOSFET driver is not working properly?

I've started to build a brushless driver by using some Power MOSFETs and some MOSFET drivers, in order to drive the Power MOSFETs. I have connected the chips as shown in the application circuit (page ...