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Participant

Join Date: May 2008
Posts: 2

# Electrical Calculator Tool Online

05/09/2008 7:13 AM

I am using Capacitor Energy Time Constant formula at www.calculatoredge.com in the Electrical Section, I was wondering does any one have the physical formula for this, please advise

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Anonymous Poster
#1

### Re: Electrical Calculator Tool Online

05/09/2008 8:08 AM

The energy "W" stored in a capacitor is equal to 1/2 times the capacitance "C" times the voltage "V" squared or W = 1/2 * C * V * V (Joules). The voltage across a capacitors terminals is equal to the stored charge "Q" divided by the capacitance "C" and the charge "Q" is equal to Current "I" multiplied by time "t". So with a little mathematical manipulation we can get...

the energy "W" in Joules is equal to "I" squared times "t" squared divided by 2 times the capacitance "C"

W = I * I * t * t / ( 2* C)

This can be manipulated in many ways for many applications.

Guru

Join Date: Jan 2007
Posts: 1024
#2

### Re: Electrical Calculator Tool Online

05/09/2008 10:10 AM

The Time constant (Tau) is simply the Load Resistance X Capacitance

Charge stored in a capacitor: Charge Q = CV where C is the capacitance in Farads

charge Q is measured in coulombs (C)

Energy stored in a capacitor: Energy stored, W = ½ QV = ½ CV2 joules

1 joule = 0.00094781712 btu

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