RadioBanter - View Single Post - connecting dc supplies in parallel for more current

October 29th 03, 06:16 PM

"Jim, N2VX" wrote in message . ..
On 27 Oct 2003 19:02:07 -0800, (clc) wrote:

Im still trying to come up with a high current DC supply for my mobile HF rig.
I have 4 - transformers that are all the same part number, there output is 4amp
at 18.5 vac. I want to hook a bridge to each & then connect the DC outputs of
each in parallel to increase current to my regulator circut.
I should end up with 17 - 18 VDC @ 16 amps. Does this sound like it would
work ok, Im not sure about paralleling DC supplies ?

I did it with 2 of them and it worked OK. As you described use a
separate rectifier on each and combine the rectifier outputs.

Start scrounging hamfests, etc. for electrolytic capacitors. You
can't have too much filtering. In this case more is better.

For a regulator use a 7815 IC to drive several 2N3055's. ARRL
handbooks have a good example of 2N3055's in parallel. 5 2N3055's on
a decent heatsink will run nice and cool. Scrounge for heatsinks,
too. They tend to be cheap at hamfests because most people are
appliance operators.

And if you want to make life easier for the rectifiers add a soft
start cicruit using a relay. The handbook has an example of it.

Good luck and 73,
Jim

A 7815 would give 15 volts, wouldnt that be alittle high? A 7812 would be a
little low, so i thought of a 723 ang just adjust the voltage to 13.8.