Questions tagged [ohms-law]

A well known relationship that describes the relationship between Voltage and current through a device's resistance expressed mathematically as V= IR. This formula says that voltage across the device is equal to the current through the device multiplied by the resistance.

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LED strip built-in resistors too large?

I began officially studying Lessons in Electronics and as practice, I decided to detail an LED strip I've been using around the house. My results raised some questions around the LED voltages on the ...
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What is a multimeter at its core?

We know that, thanks to Ohm's Law: If you have an ammeter, you can put it in series with a resistor of known (usually large) value and now you have a voltmeter (after rescaling ofc). If you have a ...
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Why does a 12V, .5 AMP fan work in a PSU but a 12V, .125A does not? (both are three wire fans)

Completely new to electronics and I'm learning by trying to replace a bad PSU fan (bad bearing but no power problems to the fan). The original fan was 12V, .5A. I bought a rinky dink fan that was too ...
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Computing voltages over resistors [closed]

How do you use the combine/redraw method to find the voltages of the different resistors?
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Double loop, double voltage source circuit analysis problem, with three unknown voltages/currents, using Kirchhoff's laws and Ohm's law

I'm currently studying the textbook Fundamentals of Electric Circuits, 7th edition, by Charles Alexander and Matthew Sadiku. Chapter 2.4 Kirchhoff's Laws has the following practice problem: Find the ...
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Why does the voltage decreases when current increases?

I have a 24V battery powering a brushless DC motor. When the motor runs at low RPM and draws, say 10A, the battery reads 24V. If I go full throttle for a second, motor will draw 60A and battery will ...
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Current calculation - basic circuit

I’m just starting off, and I’m watching a series of videos about the basics of electric circuits. https://youtu.be/lf0lMDZVwTI As you can see in the the picture, the teacher solved the current of the ...
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Calculate series resistor value for LED on 220 Vac RMS supply

The traditional way to find the resistor value I can find on the internet is: (Input Voltage - Forward Voltage) / Current In my case, the Input Voltage is 200 Vac, ...
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Help a beginner understand if a design is correct

I'm fairly familiar with Ohm's law and I did some calculations I'd like experienced engineers to confirm if it is correct or point where I made a mistake Here's the idea I want to power a self-made ...
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Calculating line currents in three phase grid

My original network looks like this: I'm trying to find the line current $$l_{l, 1}$$ the red one at very top. Here is what I have done: I converted the delta impedance circuit in the right to star, ...
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Ohm's law Vs. Ohm's relation (which one is right)?

Ok, so this might be a stupid question but I just had to ask. We are all taught that Ohm's law is: V = IR I have heard some people that insist that it should be called Ohm's relation instead of ...
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If voltage and current are inverse to each other, how do we get higher power?

I am dazzled; I'm young (teen) so am not too good, but I am wondering if current is proportional to voltage, how do we get high power? What I'm trying to say is that if we were to have a 5 V supply, ...
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If a voltage source is current limited does this actually mean that the voltage across the load is limited?

For the past while I've been struggling to wrap my head around electricity. One thing that has puzzled me to no end is the relationship between current and voltage. On paper it's a really simple ...
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Why does my 120V 40W lightbulb only have 26 ohms across it?

I thought that if the voltage source is 120V and the lightbulb is 40W then the current would be 1/3 of an ampere meaning that the resistance of the lightbulb would be 360 ohms. But when I checked it ...
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