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

[Richie Burnett]

I use a Fluke I30S to measure supply currents.  You just clip it over the 
wire that the current is flowing in, (you don't need to break into the 
circuit to add a current sensing resistor or anything.)  Can currents with 
AC and DC components.  You can either connect it to a multimeter to display 
the average current value, or look at the waveform on an oscilloscope to get 
peak current, average, RMS, etc...

It's not as cheap as a 0.1 ohm power-resistor, but there are other copy-cat 
current probes that are cheaper than Fluke.

-Richie,




-----Original Message----- 
From: Vladimir Pantelic
Sent: Thursday, December 10, 2015 2:58 PM
To: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] measuring dc current max/draw of psu with a scope or 
multimeter??

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.


_______________________________________________
Synth-diy mailing list
Synth-diy at dropmix.xs4all.nl
http://dropmix.xs4all.nl/mailman/listinfo/synth-diy


-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2016.0.7294 / Virus Database: 4483/11152 - Release Date: 12/10/15