Understanding resistance more.

[XRZ]

Okay, so I'm a bit confused about how resistors work.
I understand they increase the resistance of circuit an all, but look at this example:

We have a circuit that's resistance is 0.003Ω and a power supply of 1kW, based on ohms law we can calculate the Voltage: 1.73V so the current flowing would be: 576.6A.

So, if we would like to increase the applied voltage to a certain component in that circuit, we can increase the resistance correct?
What if the resistance across that component is the same at 0.003 Ω ,and the voltage would be the same at 1.73V, even when adding a resistor to try and increase it?

Side question: Are there resistors that can handle massive amount of dissipate power? I mean, in kW or MW of power?
I was thinking about kW or MW of power converting massive current into higher voltages or vice verse, that requires a unique resistor right? And can a resistor be designed to increase resistance by a few mili-ohms and dissipate a lot of power?

 

[Gryd3]

Usually power supplies are either constant current, or constant voltage.
I have never heard of a constant power supply before.. (Anyone else)

With a constant voltage supply you can only increase voltage across a specific component by decreasing any resistance that may be in series with it, but you will not exceed the voltage of the supply. (There ARE ways to get a higher voltage, but this is for a different topic)

With constant current supplies you can increase the voltage provided to the entire circuit by increasing the resistance of the entire circuit... but this would typically keep the voltage across each component in your circuit the same. (As the voltage across any single component would be a function of the current going through it and it's resistance.)

This is based on sample Resistor Circuits for lab use... Doing these experiments with ICs will cause damage.

Your side question is incorrectly founded.
A resistor will dissipate power as heat... You can find large resistors that will handle 1W 5W etc, but you will end up with a heater, it will not do anything useful beyond heating up.
Transformers are simple devices that you can use to convert high current low voltage to low current high voltage, but this will only work with alternating current. Alternatively there are devices such as Boost and Buck converters that can do the same thing to a limited degree.

 

[Gryd3]

I remember your post regarding the C-EMF...
Are these experiments you are doing on your own free time? Are you teaching yourself?

V=IR and P=VI are the two basic equations that could easily answer your questions and are usually the first thing taught in electronics. If you happened to take physics, you should have been taught this twice.

What are you trying to accomplish?

 

[BobK]

Side question: Are there resistors that can handle massive amount of dissipate power? I mean, in kW or MW of power?
I was thinking about kW or MW of power converting massive current into higher voltages or vice verse, that requires a unique resistor right? And can a resistor be designed to increase resistance by a few mili-ohms and dissipate a lot of power?

Why would you ever want to? Power dissipated in a resistor turns to heat and is wasted power (unless what you really want is heat.)
And you seem to be under a misconception. A resistor does not "convert" current into voltage in the sense that you are using the term. It basically wastes power by losing voltage across it when a current flows through it.

Bob

 

[(*steve*)]

Side question: Are there resistors that can handle massive amount of dissipate power? I mean, in kW or MW of power?

Side answer: In a former life I worked at a place what had electric trucks. They had a huge diesel motor powering a generator which drove the motors in the wheels (similar in effect to trains as it happens).

These vehicles had "dynamic braking" which consisted of a huge resistor bank that dissipated the energy generated by the wheel motors. I'm not sure of their rating, but it was a lot more than a couple of kW.

For another example closer to home, look at the normal bar radiator. A 2.5kW model is relatively easy to find.

A little googling reveals that one model of truck has a 4.5MW resistor in it! Oh, and back to information from my former life, when descending a long downhill haul road at this particular mine there was a danger that the dynamic brakes of a fully laden truck (possibly with 220 tonnes of rock on it!) could catch fire. This is one reason why primary crushers are normally near the top of the mine, not the bottom. Oh, and if you think 220t is a lot, the truck linked to can carry 360t!!