hi
i want to remove the noise in the voltage across the resistor.
for that i want to add one capacitor parellel to the resistor please tell me how can i calculate capacitor valuevalue
Adding a capacitor across the resistor will change the frequency response of the circuit so the capacitor value will depend upon your circuit and its required frequency response. What is your circuit?
More or less, for a power supply you can use 1,000uf per amp of current.
A little closer- dV=Iload/2fC for a full wave rectifier. Use fC for half wave. C=capacitance, f=frequency, dV=ripple voltage
If that's the wrong approach, maybe you can squeeze a low pass filter in your circuit.
Trace the noise back to its source and correct it there.