Can I Use My Hobby Resistor On A/c Circuit?

I want to place a resistor onto an a/c wire in a 120v device that can carry no more than 20 amps.

I searched the web to see if there's any difference between a/c resistors and dc resistors but I can't find any information.

I remember some time ago that I was told that a small resistor that I use in my hobby circuit board will not work on a/c.

I can't find what will. Does the a/c have to be converted/transformed first or is there another way?

What do you want to do?

Why are you looking to fit the resistor?

there are different grades of resitor for different voltages, most are 12/24v

Interesting question..

and good to see that someone is thinking about things before just guessing and trying them...

My question would be...

What do you call a "Hobby Resistor"?

Resistor come in all sorts of shapes, sizes, ratings, construction etc..

They are used in gazzillions of everyday electronic and high power applications on both AC and DC circuits...

Resistors themselves will operate with current flowing in either direction, therefore they can work in ac & dc applications quite happily.. 

But as with most electrical components they have a maximum power rating before their internal structure starts to overheat and possibly cause irrecoverable damage...

As   Resistance is proportional to Voltage/Current   R=V/I

and   Power is proportional to Current x Voltage    P=V*I

Any situation where higher currents will flow through your resistor will increase the power it has to dissipate 

So applications with lower current, or lower voltage will automatically have lower power rating resistors..

If you resistor is of a higher ohmic value that in itself will reduce the amount of current.. and power through it..,

BUT...

if you are trying to put a low ohmic value resistor across a higher voltage  (AC or DC) you could quite easily burn out the resistor.

However..

you also mention..   120v circuit & 20amps...

a device consuming 2400watts?

I think we need more info of the actual spec of your "Hobby Resistor"

and exactly where you hope to connect it?

I presume you have read....

http://en.wikipedia.org/wiki/Resistor

Guinness

My guess is that the OP is from USA.....but what do I know?

See wife for details.......

don't forget that AC voltage is RMS, so 120V ramps up to about 200V at peak (to lazy to get out the calculator to do it right)

forgive me

I've only played with resistors at the 12V DC/1000mA level.

12 Watts.

Yes, a 2400 watt resistor is what I am looking for.

I was guessing that they were labeled for AC as I didn't think DC(what I'm calling hobbyist) resistors could handle that much power. I guess not that there's any difference between using a resistor on dc/ac I guess. But at the level of power in the application.

So all I have to look for is 2400 watt resistors. What ohms would the resistor be?(6ohms)

In my searches I don't see resistors labeled to support more than values in the hundreds of watts, none in the thousands.

Wow, the resistor would have to dissipate 2000 watts? Is that right? That's a crazy amount of heat isn't it? Pretty much any kind of plastic device would just melt unless that was heatsinked away right?

I've used an auto transformer for low power devices in the past, but 2400W is quite a load...

Ya, I didn't realize all that until the querying here. I will just look at per device power needs and not worst case scenario.

Thanks for the help.

DkEnrgyFrk said:

Wow, the resistor would have to dissipate 2000 watts? Is that right? That's a crazy amount of heat isn't it? Pretty much any kind of plastic device would just melt unless that was heatsinked away right?

Click to expand...

2kW electric heater should be a good substitute....

I was going to reply earlier, but the tread was locked. It seems unlocked again.

Rather than just asking us about a "hobby resistor", could the OP come back and tell us exactly what he is trying to achieve and we might be able to give some proper advice.  i.e a circuit diagram or some idea what he is trying to connect to what.

DkEnrgyFrk said:

Ya, I didn't realize all that until the querying here. I will just look at per device power needs and not worst case scenario.

Thanks for the help.

Click to expand...

What are you trying to achieve?

Tell us what your end result needs to be and we may be able to help.

kW rated resistors are available if needed, they tend to be wire wound in general.

http://www.rhopointcomponents.com/very-high-power-resistor-assemblies-3kw-12kw-ew-series.html

http://www.resistorsonline.com/wire-grid-resistors.html

Not quite...  "hobby"

:innocent