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  #1  
Old 11-07-2010, 01:25 PM
j4570 j4570 is offline
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Series Power Supplies?

I need 90 VDC to test an old battery radio.

Can I hook up a couple of triple power supplies (each is 5V/20V/20V and can be added together for 45V, then I need two of them) to get 90 VDC? Or is there some ground problem/issue I am not aware of?

I'll post over in videokarma too, since this is for an old radio.
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Old 11-07-2010, 01:49 PM
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bandersen bandersen is offline
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It depends on the power supply. If the outputs are floating (negative terminals are not tied together internally), it should be fine. I use an HP 6228B dual 0-50V connected in series to get 90 volts.
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Old 11-07-2010, 02:31 PM
j4570 j4570 is offline
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I can do the supply itself.

What about using two seperate supplies??

Jason
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Old 11-07-2010, 03:45 PM
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Again it depends on the supply. If the negative terminal is connected to either the neutral or ground on the AC plug, it won't work.

perhaps you could just build a 90 volt supply from scratch ? Here's a very simple transformerless circuit http://www.antiqueradio.org/bsupply.htm
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Old 11-07-2010, 05:29 PM
j4570 j4570 is offline
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I ran across that page a while back, forgot about it. I might do that if I don't do somehting else. The radio I have only needs 1.5V and 90V. I guess I could always go the 10 9V route.

I want to see if this works before I construct a permanent supply for it.

I'll look on E-bay for a bigger supply, always a good excuse........

Jason
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Old 11-08-2010, 02:18 PM
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You could go to the dollar store and buy ten cheap 9-volt transistor batteries and snap them together + to - and get 90 volts for your test. You might be surprised how long they would last, too. If you need intermediate voltages just capture a wire between snapped terminals at the appropriate point between batteries. Ditto for your 1.5 volt supply: put a couple of D cells in parallel for more amp-hours.
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Old 11-08-2010, 05:30 PM
j4570 j4570 is offline
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I was under the impression that the 9V's wouldn't last that long. Looks like from some basic informaiton, Alkalines would last at least 10 hours.

If I had enough AA battery holders (I used to have tons for old CB's, 8 each for 12 Volt, probably tossed them), I could get close with AA rechargeables I bet. Well at least 1/2 there.

Jason
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Old 11-11-2010, 07:27 PM
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http://home.comcast.net/~morrised200...structions.pdf

Simple!

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