I've attained most of the material I need to build my first power supply. The specs are mostly dictated by the parts I have. My intention is a dual isolated variable output power supply that I can connect in series to give negative voltages.
Below is the "final" draft of the circuit that I'll be implementing. I'll add in fancy pass transistors and capacitor discharge transistors and other things once I completely understand how they work.
I've set up a basic form of this with a single output and no decoupling capacitors or protection diodes on a breadboard and it worked well.
Clarification: I pulled a single bridge rectifier package out of an old TV which is why I have both a packaged bridge and a diode bridge on the schematic. Other than that and the transformers, the circuits are identical.
EDIT: Fixed schematic.
So here are some things I would like to ask:
- I'd like to solder the primary of the 500mA transformer to the primary lugs of the larger transformer so I don't have to branch the mains wire to it separately, is this fine?
- Is it fine if I stack the two transformers on top of each other?
- If I had both outputs connected in series, would I be limited to 1A due to the second transformer only providing 500mA? I don't need that much current but I'm just curious if I'd run into trouble since the transformers are unbalanced. I have a 9V 15VA transformer as well, would that be better matched?
- What amperage of fuse should I use? I'm worried about magic smoke….
- How damaging would a shorted/max current output be on this circuit?
- Any general advice/improvements?
Thanks for your assistance.