Is there a way to test a power supply?

cscool36

cscool36

Full time elf
Joined
Jan 9, 2011
Messages
168
Location
Belrose NSW
Hi all,
Is there any way of testing a power supply eg 5 volts Dc 250watt without using lots of lights.
Thanks
Colin
 
250W @ 5V is 50 Amps so that can be hard to do with things laying about the house. :D

You could make up a dummy load with ten 1 Ohm, 50 W resistors in parallel (to get 0.1 Ohms) and fan cool them. No matter which way you look at it, you still need to dissipate 250 Watts worth of heat.

I made a dummy load for testing DC controllers the other week. It has six 4.7 Ohm 100W resistors mounted on a tunnel heatsink with a fan. That was good for pulling about 15 Amps @ 12V (180W).
 
Car headlights is actually a fairly easy load to hook up to power supplies. Because the resistance of the filaments is a lot lower when they are cold there is a big inrush. For example a 12V 100W light won't just draw 8.3A at switch on. It's probably more like 40A until the filament is hot. Hooking up a 12V light to a 5V supply will provide fairly significant load.
 
Thanks
AAH and David_AVD for your information.
I might try the 12v light first.


Colin
 
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