Power Supply Q

Absolute

New member
Bought a Tekpower TP3005T https://www.amazon.com/Tekpower-TP3005T-Variable-Linear-Supply/dp/B00ZBCLJSY

Trying to hookup the leads to find a short onboard using constant voltage/constant current mode. Runs a fan or lights that I hookup to it successfully but when I hook the negative to ground and the positive to ppbus g3h p.rail the power supply drops voltage from the 12.5v I preset it to 0.00v and blasts the max amperage I set which is 5.2amp once I attach it to the shorted rail. Do I need a better power supply, ie. agilent or am I missing something. Sorry for the noob question but I'm beating my head against the wall
 

dukefawks

Administrator
It's a dead short so of course the voltage will drop to 0 and max out the current. Something must be heating up now on the board for sure.
 

LearningMan

New member
Bought a Tekpower TP3005T https://www.amazon.com/Tekpower-TP30.../dp/B00ZBCLJSY

Trying to hookup the leads to find a short onboard using constant voltage/constant current mode. Runs a fan or lights that I hookup to it successfully but when I hook the negative to ground and the positive to ppbus g3h p.rail the power supply drops voltage from the 12.5v I preset it to 0.00v and blasts the max amperage I set which is 5.2amp once I attach it to the shorted rail. Do I need a better power supply, ie. agilent or am I missing something. Sorry for the noob question but I'm beating my head against the wall

Look up foldback circuits and crowbar circuits and you'll get an idea of why it drops the voltage.
Voltage will drop anyway if there is a dead short because there is a 0 impedance path to ground.
You don't need a better PSU. You can make your own to do the exact same job (for your purposes) for about £15. LM317 a couple resistors / caps and a crappy eBay LED panel volt meter.
 
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