# Questions tagged [resistors]

A resistor obeys Ohm's law (V=IR); the current through it is equal to the voltage across it divided by the resistance (equivalently $I=\frac{V}{R}$)

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### Power Rating of a HV resistor

I am conducting a project to measure Breakdown Voltage and would like to use a protection resistor, please see below. When breakdown happens I will have something like In this case the Power ...
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### Do I need a current limiting resistor with an industrial rail DIN optocoupler?

I'm going to use this industrial opto-coupler: Optocoupleur RS PRO, montage Rail DIN, 6 mA In its specs document they don't mention the need of a current limiting resistor. I always add a current ...
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### What happens if a ceramic power resistor is heated well past its rating?

What would likely happen if a ceramic power resistor was powered well over its power rating (for test/learning purposes and likely buried inside a bucket of sand)? By "well over", I mean 10 ...
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### Activate arc lighter with Arduino

I have a SaberLight plasma arc lighter, and I have taken it apart for a flamethrower project. I would like to use an Arduino Uno to programmatically activate the arc lighter. Using the Arduino Uno, ...
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### Which way to read this five band resistor?

Sorry for this basic question. I have a problem determining which way I should read band on the resistor below. I know it's left to right, but which side of it really is "left"? As far as I ...
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### Can I use lower wattage resistor if I’m using a high voltage power supply?

I can use a higher gauge wire with the same wattage if I use a higher voltage so the current is lower. Can I do the same with resistors? I have a neon sign transformer that’s 450 watts at 15 kV and 30 ...
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### Will a resistor reduce voltage without current flow?

I asked a question where I was trying to figure out how my truck controls the speed of its blower motor. This answer provided the following diagram showing that it uses a set of resistors in series to ...
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### How to reduce power drawn by a resistor heater?

I am rather new in this field. On 220V AC industrial power supply, a 6 ohm resistor heater (nichrome wire, 0.40 ohm/m, 15 m) will draw about 8067 watt of power. About 2400 W are needed. What are the ...
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