### Author Topic: How to calculate RC constant with 2 capacitors?  (Read 269 times)

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#### deer_force_1

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##### How to calculate RC constant with 2 capacitors?
« on: January 17, 2018, 05:03:26 am »
Hi all, I'm having trouble calculating the RC constant of this circuit.  Is it correct that you have to replace the voltage source with a short circuit and combine the resistors connected across the terminals of the capacitor? For only C1 or C2 I see that the RC constant is ( R1 || (R2+R3) )*C1, and similarly for C2 ignoring C1, but how can I calculate the RC constant of the whole circuit?

Thank you

#### TheUnnamedNewbie

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##### Re: How to calculate RC constant with 2 capacitors?
« Reply #1 on: January 17, 2018, 06:15:04 am »
This circuit is not a single pole/zero circuit. Hence it can't be described with only one timeconstant... Unless C2 is so small it is not dominant?
The best part about magic is when it stops being magic and becomes science instead

#### Wimberleytech

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##### Re: How to calculate RC constant with 2 capacitors?
« Reply #2 on: January 17, 2018, 07:16:10 am »
This circuit is not a single pole/zero circuit. Hence it can't be described with only one timeconstant... Unless C2 is so small it is not dominant?

This is correct!

Smf