if we connect a capacitor with charge = 5 volts , with buffer (op-amp) , will the capacitor will discharge it's voltage ? or because of high impedance will keep it's charge ?
simulate this circuit – Schematic created using CircuitLab
buffercapacitoroperational-amplifier
if we connect a capacitor with charge = 5 volts , with buffer (op-amp) , will the capacitor will discharge it's voltage ? or because of high impedance will keep it's charge ?
simulate this circuit – Schematic created using CircuitLab
Best Answer
In the ideal sense, that capacitor will hold its charge for a very long time because of the high input impedance of the FET input opamp, and slowly leak to ground. In reality, the circuit probably isn't very useful, as the bias current from the positive input of the amplfier has nowhere to go but that capacitor, so your amplifier output will probably eventually saturate at the positive or negative rail, depending on the direction of the bias current.