Here’s a great project for a multi-voltage high current power supply. This type of supply will generally output 3, 5, and 12 volts DC when fed from either 120VAC or 240VAC mains. As a licensed Ham Radio operator, I have radio equipment that requires significant current to transmit signals. Sure there are commercially available supplies for this purpose, but you’ll spend on average $200-$300 depending on how much current you require for your application. If you have a computer that is no longer useful, you can salvage the supply inside and perform the modification shown and explained in this video. I built this modified supply several years ago back in 2001 and the same unit is still powering my radio gear amongst other things.
My radio is a DC current hog when transmitting, so a stable supply of filtered & well regulated DC current is a MUST:
You can install banana binding posts for the following connections:
- DC Ground
- +12 Volts
- +5 Volts
- +3 Volts
Here is a photo showing the supply connected to my 12VDC bus, to which the radio pictured above is powered from:
This is quite useful. While I am using my radio, I can also charge a number of 5volt devices (cellphones, tablets, anything that runs of USB voltage) by putting a multiport USB hub on the 5V output. Since the current is high, devices power reliably, and charge quickly too. The 3V output is useful for powering devices like solid state high power lasers (like blue ray, or DVD burner lasers) for science projects and is well filtered and regulated.
One thing to note is that you want a supply that is rated at 350 watts or more. This power rating is often found on the manufacturer label and often lists the output current at the rated DC output voltages. By recycling these supplies, you not only get a well filtered & regulated supply, but you also help the planet by reusing electronics that would otherwise be destined for the landfill.
I can’t stress it enough: DO NOT embark on this project if you do not have a full command of electricity principles and safety methods. Voltages & current present in the switching circuitry of these power supplies CAN KILL YOU INSTANTLY if you don’t know what you are doing or otherwise touch the WRONG areas inside!!! Proceed ONLY if you know exactly what you’re doing and are knowledgeable about electrical safety methods. When modified properly, these supplies are quite safe and efficient. This is an excellent “GREEN” project that can do good for our planet. If you don’t know how to do this modification or are unfamiliar with proper electrical and safety precautions, PLEASE get QUALIFIED HELP!
Now onward to the video: