AMP / Voltmeter display on PSU

daunce

Apprentice elf
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Jun 9, 2010
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Ferntree Gully, VIC
Hey all.

I think it was the 2018 Melbourne Mini some guys had a small display on each power supply. Looking on eBay it seems a cheap way to check rough voltage and current draw at a glance.

Do they wire up to each individual output, or do you connect it to each positive terminal on a PSU?

Cheers.
 

scamper

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Jan 5, 2014
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collie
It depends on what you are trying to achieve. If you want to know the voltage and current draw for that power supply, then the voltage can be taken from any terminal on the supply, but all of the current must be taken through 1 shunt to the the meter.
If you want to find out the voltage and current for each string, then you need to run power through the meter to each string.
 

AAH

I love blinky lights :)
Community project designer
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Dec 27, 2010
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Eaglehawk
I had them on my power supplies on that demo board. All the outputs on a given power supply are directly in parallel so connecting to any 1 of them is all that is required.
Amp meters are where it gets complicated. The best option is a clamp style like David said. If you are using a shunt style meter then you will have a voltage drop across the shunt of maybe 100mV at 10A but that's just a guess based on the fair lack of info supplied by ebay/aliexpress. If you are using a shunt type meter then you have to stay within it's ratings which is often 10A for the cheapies. As there are often 3 outputs with each of the 3 outputs being rated at 30A via the connectors you would have to have multiple meters to measure all the current coming from a power supply.
A voltmeter is handy and cheap. An amp meter would be nice but for most applications it isn't practical.
 

daunce

Apprentice elf
Joined
Jun 9, 2010
Messages
78
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Ferntree Gully, VIC
Ah cheers gents. I guess I was going with gadgets rather than being practical using a multimeter.

Will keep it simple. Thanks!
 
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