Electrical Engineering Stack Exchange
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1500 questions
28
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12 answers

Is there something such as an infinite potentiometer?

I am trying to find a component, that, similar to a potentiometer, delivers an analog output, but which can be turned indefinitely in a single direction. I have tried searching for something like this, but I never quite found anything that does what…
Busti
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How to find the ESR of a capacitor

I am building a power supply circuit, and the switching regulator (L4963) calls for a low-ESR output capacitor. The capacitor in question is C3 of the evaluation board circuit. What does "low" mean? How low? Also, how do I find or calculate the ESR…
Robert Deml
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What is the purpose of "MOSFET driver" ICs

There are dedicated "MOSFET driver" ICs available (ICL7667, Max622/626, TD340, IXD*404.) Some also control IGBTs. What is the practical purpose of these? Is it all about maximizing the switching speed (driving gate capacitance) or are there other…
XTL
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What is the difference between emitter and collector for BJTs?

the (surely simplistic) model of a bipolar junction transistor one is taught in foundational physics course appears to be symmetric. - So, what is the difference between the collector and the emitter of a real BJT? If the transistor were symmetric…
ARF
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1 answer

Is there a difference between SOIC and SOP?

I'm looking at two integrated circuit packages: SOIC and SOP. They seem (almost) identical (pitch, overall size, etc...) SOP SOIC Is there any important differences between these two packages that I am overlooking?
Ryan Jensen
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28
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10 answers

How do I power/wire something that is rotating constantly WITHOUT extra batteries?

So I want to make a Lazy Susan that is rotating constantly in one direction. I also want to have some other things on top such as neon signs, moving things, and etc. Problem is I want this to all run off of one DC source. Problem is I cannot figure…
Sie
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10 answers

Is it safe to sleep in the same room with a car battery?

I sleep in the same room with 2 car batteries. I'm not a battery person so I don't know what type they are. I tried looking for voltage but didn't find it printed on the battery. They're standard acid batteries, I use them to power LED lights and…
MichaelX
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7 answers

Can I use two 7805 ICs in parallel to get double current capacity?

I use a 7805 for a project where the circuit needs a higher current (~2.8 A) at 5 V. So I assume that if I use both ICs in parallel I can increase the maximum current capacity. Would it work?
Ridham
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5 answers

Capacitor Gaining Voltage Over Time?

I recently bought two 3300uf 100v capacitors and have connected them in parallel. I charge them up to 100v and discharge them. I then hook up a multimeter and notice the voltage going up very slowly, about .01 volts every 20-40 seconds. So I…
Erik
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28
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7 answers

What exactly is a short circuit?

In my book there is no explanation of the phrase short circuit but at many places the author has used it. I had googled it. Some explain it as the flow of charge along a high potential difference while others explain it as the flow of charge along a…
MrAP
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3 answers

The mysterious case of the random leakage current

Disclaimer: I already know the solution of this circuit debugging conundrum (and it is not trivial), and I'll post it after some time, so that other people could give their contribution to this mystery story! I think it may have some educational…
LorenzoDonati4Ukraine-OnStrike
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5 answers

Why old PMOS/NMOS logic needed multiple voltages?

Why does old PMOS/NMOS logic needed multiple voltages like +5, -5, and +12 volts? For example, old Intel 8080 processors, old DRAMs, e.t.c... I'm interested in the causes on the physical/layout level. What was the purpose of these additional…
BarsMonster
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4 answers

How reliable is it to use another manufacturer's datasheet of the same part?

There is a part, 1N4148, or whatever from manufacturer A, but the datasheet from manufacturer B is more detailed, has nice graphs, etc. Is in general data for the exact part consistent between manufacturers?
LuisF
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6 answers

How to Calculate the time of Charging and Discharging of battery?

How do I calculate the approximated time for the Charging and Discharging of the battery? Is there any equation available for the purpose? If yes, then please provide me.
Farid-ur-Rahman
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How do I make the turn off and turn on time equal in a NPN transistor?

I have a simple NPN switch, see the diagram. I feed a 100KHz square wave (TTL) to the base of this transistor and it turns on very very fast (a few nSec) but it doesn't turn off as fast, it almost takes 2uSec for it to turn off. (I am looking at…
Frank
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