Electronics questions (power handling of resistors in series and parallel)

Feek · 5 Apr 2017 at 15:32

Looks like a school question, trust me, it's not!

Total resistance is very easy to work out, the total power handling capability is not quite so clear.

Feek · 5 Apr 2017 at 19:30

firstborn said:
560W? (in my head on a bus)

How are you getting that?

Feek · 6 Apr 2017 at 18:00

When working with radio transmitters (this is a dummy load), I always work in Watts. Hence the reason for the question.

Feek · 7 Apr 2017 at 13:37

Hmm, something has changed and I actually won't have this exact number of resistors. All I'm going to have is 5 x 10 Ohm jobbies.

All rated at 100W, how much power can I squirt into this load?

Because they're all identical, I seem to remember that a chain of N resistors each rated for P watts can dissipate NP watts. So 500 watts?

Feek · 7 Apr 2017 at 16:51

@Bear Yes, I know that. The resistors I'm using are specifically non inductive but I appreciate that the higher in frequency I go, the things will vary. Five resistors in series is (for example) a good chunk of a wavelength at 23cms. It's largely going to be used for HF anyway or maybe up to 144MHz at a push. Once it's all built, I'll do a full sweep to see what the impedance is.