Measuring average current

ShinAce
ShinAce Posts: 1,194
edited January 2008 in DIY, Mods & Tweaks
I'm on a quest to get my post count to 10 so I can send a PM to a buddy.

But, I do have a valid question. I've built a headphone amp based on the 5532 opamp. The quiescent current is roughly 8 mA for both channels. With music, average is about 8.5 mA, but at higher volumes, it can reach 15 mA. I'm trying to find what the average power consumption would be for classical music.

I've though of using caps to filter the power supply(12 V battery). With this scheme, the leads can be placed before the cap so that you are only measuring the power delivered by the battery. The power delivered to the circuit and the cap to charge it back up adds up to the total power used by the circuit.

Is there an ideal value of capacitance and charging resistor to have it smooth out the spikes properly. Remember that the voltage is 12 v - 18 v (regulated) and average current draw is in the neighbourhood of 10 mA.

Please don't suggest I log the current over time on computer and integrate, that would be way too much trouble.