'Driving' Capacitive loads

[gauthamtechie]

What is meant by "driving" capacitive loads ? Some amplifiers mention that they source and sink a high current quickly to keep the voltage stable in capacitive loads.

Does sourcing and sinking vary the charge on each plate of capacitor, rendering stable voltage? How does the voltage change initially?

 

[crutschow]

It requires large currents if you want to rapidly charge and discharge a capacitor thus you need a driver (amplifier) capable of supply both large source and sink currents to the cap.

Stability generally refers to the stability (no oscillations or significant overshoot when amplifying signals) of an amplifier with feedback. Large capacitive loads can often change the loop phase response and thus the stability of feedback amps. That's why they may mention operation with capacitive loads.

Don't understand your question about "charge on each plate of a capacitor". Except at extremely high frequencies the charge on the plates is uniformly distributed when the capacitor is charging or discharging from a change in the voltage across it.

 

[gauthamtechie]

Thank you for the answer. The part about charge on the capacitor: that came out of confusing myself with many things at once. I'm able to understand better now.

Does the term 'sinking' refer to the negative current supplied to the capacitor to decrease the charge on the capacitor and hence the voltage across it?

 

[crutschow]

.....................
Does the term 'sinking' refer to the negative current supplied to the capacitor to decrease the charge on the capacitor and hence the voltage across it?

Yes. "Sink" is normally current flow to ground and "source" is normally current flow from the voltage supply.