# Re: Need a calculator that knows about coulombs

On 12/22/2015 06:02 PM, John Hasler wrote:
Gene Heskett writes:
In this case, the size of a capacitor hooked to a square wave source,
and I want to know how much charge is transfered for every full cycle
of the input square wave.
Zero assuming linear source and load impedence.
And assuming the square wave is symetrical about zero. If I recall Q=CV where C is in farads, V in volts and Q is in coulombs. With R (circuit resistance) = zero. The Voltage on C will instantly be the supply voltage an Q=CV applies. In short, it is a steady state problem. If R is not zero then there is a charging time constant involved. But if the on period of the square wave is at least 5 times the time constant of the circuit, it's still a steady state problem. As I recall the TC = RC seconds. If the period of the wave is less than 5 times the TC then things get more complicated. Look up time constant in wikipedia will probably give you the answer. In any event, any scientific calculator will do the job.

Gary R.