# Discharge time of 2 capacitors in parallel

Discussion in 'General Electronics Discussion' started by Ping, Feb 9, 2016.

1. ### Ping

4
0
Feb 3, 2016
Hi,
Can someone please tell me if this is correct?

If I put 2 capacitors in parallel in a DC circuit, the capacitance adds and the total ESR is the inverse of the two ESR's added, just like any other resistance. Therefore to get the quickest possible discharge rate I need 2 capacitors with the highest possible ESR.

Is that right? If not, someone correct me!

2. ### Ratch

1,094
335
Mar 10, 2013
You need to get your understanding of ESR checked and calibrated. ESR is an AC phenomena, and is a measure of the lossiness of capacitor. You need to read and understand the mat4rial in this link. http://my.ece.ucsb.edu/York/Bobsclass/194/References/General/ESR of Capacitors.pdf

Ratch

3. ### Ping

4
0
Feb 3, 2016
Good article Ratch. Thanks - although much of it is beyond what I'm trying to do.
So you mean that all the dissipation factors will slow the discharge?
And if I put 2 capacitors in parallel will the total resistance still be the sum of the inverses? Will that make the discharge faster?

4. ### Ratch

1,094
335
Mar 10, 2013
Are you talking about the RC time constant? Depending on what kind of capacitor you have, the physical resistance should not be more than a few ohms. How does that compare with the other resistance in the circuit? Is it worth worrying about? If necessary, I can calculate the response of two capacitors and their physical resistors in parallel, or one double value capacitor and resistor in series. I think probably the additional resistance in the circuit will swamp out any of the capacitor physical resistance no matter how you configure them..

By the way, you mentioned capacitor discharge. What is the capacitor discharging? Before the capacitor discharges, it has to charge with something. What is that something? Anyone?

Ratch

5. ### AnalogKid

2,573
740
Jun 10, 2015
Since your question are not clear, can you post your schematic? It will save a lot of time.

ak

6. ### supertech007

5
1
Feb 28, 2014
A capacitor of a lower uf rating will discharge faster if the voltage remains the same

7. ### Ratch

1,094
335
Mar 10, 2013
Voltage is its rating. Value in microfarads is its capacitance value, not rating. What is the capacitor "discharging"?

Ratch