I converted a 350W ATX computer power supply to provide me with a 12vdc source for some radio equipment (it's meant to be powered by your car). This will give me 15 amps @ 12vdc.
Put the PS_ON wire on a switch that gets pulled to ground, put an LED with 330ohm resistor on the POWER_GOOD wire (probably should be less since it's not as bright as I'd like), put a 10ohm 10watt resistor on a +5v wire and placed it on the heatsink already in the box (because a switching psu requires a load to function), and put a +12v wire on a terminal that I can use with bare wire or banana plugs.
Tested it under no load (except for the load I put on the 5v rail) and got +11.7v. With a 100 watt light bulb hooked up, I had +11.59v. On the actual load (the radio) operating at 65 watts output (about 14-16 amps draw on the 12v rail on the psu depending on efficiency), I get a voltage drop to +9v then the psu regulates it back up to 11.7v. When I cease transmitting, it jumps to +14v and then it gets regulated back down to 11.7v. The radio is capable of 13.8v +/-15%.
The parts to build it cost me nothing. Seriously, nothing. I had the psu from a dead pc and I had the resistors, LED, switch, terminal blocks, solder, heatshrink tubing, etc etc all on my work bench. Normally I'd pay $80 for a regulated 12v psu capable of that current.
Score.
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Put the PS_ON wire on a switch that gets pulled to ground, put an LED with 330ohm resistor on the POWER_GOOD wire (probably should be less since it's not as bright as I'd like), put a 10ohm 10watt resistor on a +5v wire and placed it on the heatsink already in the box (because a switching psu requires a load to function), and put a +12v wire on a terminal that I can use with bare wire or banana plugs.
Tested it under no load (except for the load I put on the 5v rail) and got +11.7v. With a 100 watt light bulb hooked up, I had +11.59v. On the actual load (the radio) operating at 65 watts output (about 14-16 amps draw on the 12v rail on the psu depending on efficiency), I get a voltage drop to +9v then the psu regulates it back up to 11.7v. When I cease transmitting, it jumps to +14v and then it gets regulated back down to 11.7v. The radio is capable of 13.8v +/-15%.
The parts to build it cost me nothing. Seriously, nothing. I had the psu from a dead pc and I had the resistors, LED, switch, terminal blocks, solder, heatshrink tubing, etc etc all on my work bench. Normally I'd pay $80 for a regulated 12v psu capable of that current.
Score.
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