Bench AC Supply

Over the last couple of days I have been working on a Bench AC Supply. This is an essential piece of equipment that every workshop should have, some how i have managed not to need one up until now. The project itself if very simple and can be modified very easily to suit any input and output voltages.

The supply consists of five parts:

  1. Case/Chassis
  2. Power Switch
  3. Fuses
  4. Low Range Transformer (0-15v 2A)
  5. High Range Transformer (12-30v 1A)

My supply consists of the following outputs:

  • 6.3v (2A)
  • 7.5v (2A)
  • 9v (2A)
  • 10.5v (2A)
  • 12v (1A)
  • 12.6v (2A)
  • 15V (1A)
  • 15V (2A)
  • 17.5v (1A)
  • 20V (1A)
  • 24V (1A)
  • 27.5v (1A)
  • 30v (1A)


The Transformers chosen were done so for maximum versatility, The transformers secondary windings are all series windings making it possible to centre tap the transformers. For example using the high range transformer it is possible to centre tap to get 15-0-15 or 12-0-12 This makes the supply suitable for even more projects.

The Two transformers consen are ARLEC 6672A and ARLEC 6978, both being multi-tapped transfomers. Many other transfomers are suitable for use in this project, these were chosen due to several factors, Avaliable voltages, Current rating and Physical Size.


ll of Materials:

  • 1 x Metal Enclosure
  • 1 x IEC Mains Connector
  • 1 x 250v AC 3A switch
  • 2 x Fuse Holders
  • 1 x ARLEC 6978
  • 1 x ARLEC 6672A
  • 15 x Bannana Socket, with Binding Post
  • Optional Power LED

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