Project files: Little helpers – Fuseboards

The third part of my “little helpers” project series consists of a few connector/fuse boards for power supplies or for testing/lab use. Not exactly the world’s most interesting PCBs, but still  – they can be quite useful so I decided to publish them anyway 🙂

What is it?
These are simple fuse-boards with LEDs to be used on the secondary side of a transformer or DC PSUs (such as switchers). There are two versions:

One version can be used to combine two AC or DC voltages to provide a center-tapped voltage. The circuit works on both AC and DC so can be used for example for wiring up two secondary windings on a transformer to provide a +/- voltage or for combining two DC power supplies to do the same.

The second type of board is more or less identical, except that the ground plane is split so they are “passthrough” for the input voltages. This is useful for instance if you want to put fuses between the transformer secondary and a PSU board that already has an onboard rectifier and does not need (or want) a center-tapped voltage.

The boards also include fuses for both rails as well as LEDs to indicate that power is applied. If connected in the “standard” way then the LEDs are connected to the input through the fuse, so if the fuse breaks the corresponding LED will turn off.

How big are the boards?
There are two sizes of both designs:

  • The “small” one measures 2.0″x1.95″ (app. 51x50mm)
  • The “normal” one measures 2.5″x1.95″ (app. 64x50mm)

The two versions are compatible, meaning the board size and hole spacing are the same for the two versions.

What is the status of the boards?
All boards are in v1.0, meaning they have been tested and are working. (Well, to be honest I haven’t received the prototype versions of the “passthrough” boards yet, but as they are made from the schematics to the other ones I expect no issues) 🙂

Does it use any special/expensive/hard-to-find parts?
Not really. The fuses are standard 5x20mm types with holders (22.5mm lead spacing). The LEDs, resistors and diodes are all “standard” types and the terminal blocks are 5.0/5.08mm types.

Anything else I need to know?

  • On the large boards it should be possible to use PCB-mounted FAST-ON tabs instead of the terminal blocks (not tested though).
  • Note: These boards are not intended for mains voltage use!

Download design files here

Related information:
Note: Always read the “intro post” for additional important information about my designs.


3 Responses to Project files: Little helpers – Fuseboards

  1. Nice idea. I can imagine a number of projects where something like this would be helpful.

  2. Pingback: ICEpower 200AC Amplifier | theslowdiyer

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