My 2 cents worth: What you currently have is a smoke generator / heat generator. Delete the bridge tied to the 6V winding. Install a single diode=20 with anode to transformer, cathode to filter rectifier. Theory says that you don't need the extra diode but practical=20 experience says that you do, else you can see a really significant=20 negative-going spike on power-up. I was more than a full year=20 discovering that particular problem on one of my boards. The output of the single diode is full-wave rectified 6V AC (about 9V=20 on the capacitor); the output of the full-wave bridge is full-wave=20 rectified 12V AC (about 17V on the capacitor). Actual unloaded voltages on the capacitors could be significantly=20 higher if the transformer has poor regulation. dwayne At 04:17 PM 2/3/2017, IVP wrote: >Hi all, > >I've got a couple of circuits which need 3 DC rails, 5V, 7V and >13V. The 13V is ~ 50mA, the 7V ~ 100mA and the 5V ~ 200mA > >Is there any reason a multi-tap transformer can't be used with a >bridge on each relevant tap, followed by regulation for each rail >with an LM317 or 780x. I've got 15V 20VA transformers with >taps at 3V intervals > >Googling around hasn't brought up any images of somebody >doing it. More likely is to use a transformer with one secondary >and regulate down to all voltages from that or a transformer with >a secondary for each voltage > >So I could use the 12V tap -> 17VDC and derive the 3 rails from >that, I just wonder if in principle there's any reason why it can't be >done with separate bridges. I've another project in mind which >would need 6V @ 1.5A and 15V @ 50mA. It seems a waste to >rectify for a 15VDC rail and then chop most of it back to 6V > >TIA > >Joe --=20 Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA 780-489-3199 voice 780-487-6397 fax 888-489-3199 Toll Free www.trinity-electronics.com Custom Electronics Design and Manufacturing --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .