Hello,
I am making a Bench Power Supply from a Computer PSU and according to several video tutorials I watched, there is a Choke Resistor (Dummy load) to connected to the 5V rail. Someone else said it would be connected to the 12V rail.
So I picked up 2 PSUs from a local computer store to make mine. I have packed all wire colours and built in my LEDS and Switches. According to the videos I watched, a 10W 47ohm Resistor is used.
But my problem is; Without the Dummy Load Resistor, the PSU powers on and all output works but noticed the 5v rail outputs only 4.8/4.9V and 12v rail outputs 11.9v. I was testing and while having my Voltmeter connected to the 5V wire, connected a 12v LED florescent to the 12v rail and my voltmeter changes to 5.03v.
If I connect the 10w Resistor to the 5v rail, it heats up so much and begins to smoke and I have to quickly turn off the unit and remove the resistor. The same if I connect to the 12v rail.
I checked in my box and found a 5W 47ohm Resistor and tried it in place of the 10w, it heated too but not like the 10w and hooking it with the Heat sink in the PSU, it should be fine.
Connecting the 5w Load on the 12v rail, 5v rail reads 5V but the 12v rail reads 11.7v... with the resistor on the 5V rail, the 12V rail reads 12.1v but 5V reads 4.88v
What Resistor would I use or what to do to keep both rails Output stable?
Thanks.
I am making a Bench Power Supply from a Computer PSU and according to several video tutorials I watched, there is a Choke Resistor (Dummy load) to connected to the 5V rail. Someone else said it would be connected to the 12V rail.
So I picked up 2 PSUs from a local computer store to make mine. I have packed all wire colours and built in my LEDS and Switches. According to the videos I watched, a 10W 47ohm Resistor is used.
But my problem is; Without the Dummy Load Resistor, the PSU powers on and all output works but noticed the 5v rail outputs only 4.8/4.9V and 12v rail outputs 11.9v. I was testing and while having my Voltmeter connected to the 5V wire, connected a 12v LED florescent to the 12v rail and my voltmeter changes to 5.03v.
If I connect the 10w Resistor to the 5v rail, it heats up so much and begins to smoke and I have to quickly turn off the unit and remove the resistor. The same if I connect to the 12v rail.
I checked in my box and found a 5W 47ohm Resistor and tried it in place of the 10w, it heated too but not like the 10w and hooking it with the Heat sink in the PSU, it should be fine.
Connecting the 5w Load on the 12v rail, 5v rail reads 5V but the 12v rail reads 11.7v... with the resistor on the 5V rail, the 12V rail reads 12.1v but 5V reads 4.88v
What Resistor would I use or what to do to keep both rails Output stable?
Thanks.