DIY isolated power supply offer

[niftydog]

Dewds,

I'm about to order some custom wound toroidal transformers that are ideal for making isolated output power supplies. If anyone is interested (particularly other Aussies), I'm happy to order a few extras.

The transformers will have 240V primaries and 8 secondaries each rated at 12VACrms and 250mA. Using a bridge rectifier and an LM317 adjustable regulator, this will be sufficient for a maximum output voltage of 12VDC. By combining the secondaries in various combinations it will be possible to achieve any voltage from 1.2V through to 24V and even beyond. By putting secondaries in parallel you can increase the current capacity.

The toroids will be small enough to mount in a single rack unit enclosure (approx measurements: OD 70mm, height 33mm) and will have an epoxy-filled centre for simple, single bolt mounting.

The cost of each transformer will be AUD$90 plus shipping. I want to place the order before the end of this week, so you must contact me by 11:00am Australian Eastern Daylight Savings time.

The schematic is straight out of the LM317 datasheet, but the PCB layout is my own design. I can provide my layout if required for an additional AUD$10. The design is modular, so one PCB is sufficient for one output only.