Hello, I need to discharge a 100V 100milli farad capacitor from 48VDC to 0. What size resistor would I need? Thank you in advance.

 

hi c18,
You need to specify the discharge time?
E

 

Is it really 100 milliFarad, or did you mean microFarad? One will take 1000 times longer to discharge than the other.

 

It would be nice to discharge in a minute or so. It is to take the potential away while storing.

 

it is 100milli it is a large capacitor

 

Okay, in that case it would take about 5 seconds with a 10 Ohm resistor, and it would dissipate an average of 23 W over that period.

Discharge time is about 5RC seconds.

Energy is 48^2 x .1 / 2. (CV^2/2)

Power is energy / time.

 

hi c18,
Confirmation.
E

 

Wow, my math actually worked!

Thanks eric.

 

Thank you very much for your help its greatly appreciated