next topic »

[on:]

I know this is a noob question but, how can I tell how much power something is really using.

I have a small project made up of a few LED's and an atTiny85 and I would like to know how much power it really consumes so I can figure out the best way to power it.

Thanks

[Reply #1 on:]

how much power something is really using.

You probably mean how much current.
Measure the total current the project is drawing with an ammeter/digital multimeter DMM

http://www.allaboutcircuits.com/vol_6/chpt_2/4.html

[Reply #2 on:]

Place a voltmeter to measure the exact voltage from board ground to board VCC, then place an ammeter between the power ground and board ground so that current goes thru the meter.

Power = Voltage x Amps

[Reply #3 on:]

Thanks guys.

[Reply #4 on:]

You can calculate the approximate current. Knowing the LED series resistors you have used and the LED forward voltage drop, calculate the current taken by the LEDs. Then add the power consumed by the ATtiny, which you can get from the graphs in the datasheet.