parallel capacitors

Thread Starter

js60611

Joined Nov 12, 2009
3
Hello,
First time here but probably not my last, I'm sure. I need to know how do you find for current across capacitors in parallel? For some reason i am not seeing or finding this anywhere. I'm sure its user error but I need to know this. For example: 2 capacitors 0.1uf in parallel with 5.99ma. I know this splits and will be 5.99 when current exits. I've tried current divider formula but this comes up with a crazy answer or user error which is always my first thought. I am drawing a blank can someone help with a formula since capacitor values will not always be same.
Thanks,
JS
 

KL7AJ

Joined Nov 4, 2008
2,229
Hello,
First time here but probably not my last, I'm sure. I need to know how do you find for current across capacitors in parallel? For some reason i am not seeing or finding this anywhere. I'm sure its user error but I need to know this. For example: 2 capacitors 0.1uf in parallel with 5.99ma. I know this splits and will be 5.99 when current exits. I've tried current divider formula but this comes up with a crazy answer or user error which is always my first thought. I am drawing a blank can someone help with a formula since capacitor values will not always be same.
Thanks,
JS

You don't actually have current "across" capacitors, you have current THROUGH them.

However, you can figure out the current through parallel capacitors by figuring out the susceptance of each capacitor. Susceptance(B)= 2*pi*f*C, where f is in Hertz and C is capacitance. You can now just add the susceptances of each capacitor to obtain total susceptance. If you take the INVERSE of susceptance, you have reactance. You can then use the reactance version of Ohm's law to get current: I=E/X.

If you need the INDIVIDUAL currents you just take the reciprocal of each susceptance, and use ohm's law again.


Eric
 
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