









Calculation to solve for capacitance and joules, when I,
dVTotal, td, and ESR are all known.



C=td/((dVTotalI*ESR)/I)









C (farads)

Joules

Vstart (volts)

Vend (volts)

I (amps)

td (sec)

ESR (ohms)













Stack Size
and Capacitance



Number of
capacitors in stack

Stack
Capacitance (farads)

Voltage
Required

Capacitor
Voltage Rating

Capacitor
Size (farad)











Calculation to solve for dvTotal, when I, td, C and ESR are
known.



dVTotal = I *td/C + I * ESR



dVTotal
(change in voltage)

I (amps)

td (sec)

C (farads)

ESR (ohms)











Calculation to solve for td, when I, dVTotal, C, and ESR are
known.



td = C ((dVTotal  I * ESR))/I







td (sec)

I (amps)

dVTotal (volts)

C (farads)

ESR (ohms)










Notes:




Input field



Calculated field



I = Current in Amps



dvTotal = Vstart Vend, The change
in voltage, from the start to end of the discharging time.



Vstart = Initial voltage



Vend = Ending voltage



C = Capacitance in Farads



ESR  Equivalent Series Resistance
in Ohms



ΔT = Derating factor, which is
substracted from the maximum temperature specification of the capacitor.



R_{CA} = Thermal resistance case to ambient



Note: Calculation assume a constant current.


