[sdiy] measuring dc current max/draw of psu with a scope or multimeter??

[Vladimir Pantelic]

On 10.12.2015 15:48, Dan Snazelle wrote:
> im trying to figure out if this is possible witn regular tools
> 
> i know i could buy a dc ammeter but those are expensive
> 
> ive also read about current probes but some of these seem to saturate at 500ma dc
> 
> so
> 
> i figured there must be a way to test current with a resistor and voltage
> 
> 
> any ideas??

if you put a 0.1 Ohm resistor in-line with the PSU, then a current of 1A
will give you a voltage of 0.1V that you can read/measure with the
scope. if the voltage drop is too high, you can go to a lower resistance
as long as you can reliably measure the voltage. make sure the resistor
has a tight tolerance e.g. use a precision shunt.