A 5V 3A Power Supply For Raspberry Pi Projects

Power supply

There are lots of plug-top power supplies with the correct 2A or 3A rating for Raspberry Pis. However, in many instances I need to use mains voltage inside an equipment case so do not want two supply cables connected: mains and 5V. In these situations I have sometimes used a Drok bare PCB power supply but the small ones are barely enough to run the Pi. Alternatively, I have built my own 5V supply on Veroboard with a block transformer, full-wave rectifier and an LM7805. This isn't ideal either because of the heat output from the regulator and the Veroboard circuit.

I have recently found some inexpensive 5V 3A enclosed supplies on Amazon that are suitable for mounting inside equipment. They were £3.75 each originally but have recently increased to £4.66 - not sure if this is the weakness of the GBP or a general price increase. Similar power supplies with the same model number are £10+ at places like CPC - here's a link to the datasheet. Delivery was expected between 18-28 days but it actually arrived after 11 days.

It has five connections:

There is also a potentiometer to adjust the 5V output so that if you have a fixed load you can make the voltage 5V exactly.

What About Voltage Drop-Off?

With an inexpensive power supply you might expect some voltage drop when fully loaded but it only dropped from 5V at no load to 4.98V at 3A load. I shall certainly be using these in future projects.