# summing amps and volts ?

Discussion in 'General Electronics Chat' started by energyhead, Jan 23, 2012.

Jun 23, 2011
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Hello anyone, I hope this entry level question is in the correct forum. I read the volume on current and voltage. Still so much to learn. I want to know in theory if I can take say 99V at 1 miliamp from one source and sum it with 1 volt at 100Amps from another source to end up with 100 Vs at 100.01 amps to power a motor. What would a basic summing circuit look like?

Dec 26, 2010
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As they say, there is no such thing as a free lunch. Summing circuits perform analogue mathematics, but they cannot deliver more energy than they take in.

Is this meant as some kind of a joke?

3. ### MrChips Moderator

Oct 2, 2009
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There is no practical circuit to accomplish what you are asking.
Current and voltage are not independent. They related by Ohm's Law.

You can sum the two voltages in a series circuit to give 100V.
You can also sum the two currents in a summing junction.
But you cannot sum both voltage and current at the same time.

BTW 1mA is 0.001A

4. ### davebee Well-Known Member

Oct 22, 2008
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It's kind of an unusual question.

But if the voltage and currents were AC, then I suppose that a transformer with the right windings would be able to accept two inputs like that and would be able to power a load with the sum of the input power.

Dec 26, 2010
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The sum of the input powers is the best that could be hoped for. The OP is hoping to start with 99mW and 100W and end up with over 10kW.

Hang on chaps, isn't this just ever so slightly over-unity!!!

6. ### davebee Well-Known Member

Oct 22, 2008
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ah, you're right. I didn't read the numbers.

7. ### MrChips Moderator

Oct 2, 2009
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Nah. This is not over-unity. This is over his head.

Jun 23, 2011
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Yes you are all correct and most appreciated for you responses. I will attempt to clarify, Over my head most deffinetly....overunity dont I wish but no... my goals are less lofty. I am constructing a wind turbine which has windings that supposedly will produce a great deal of amperage at almost no voltage. I have another device I want to construct which is a wind driven static electric generator which produces lots of voltage at little amperage so I end up with LOTS of voltage and amperage each a different source but in order to power a big electric farm motor demanding up to 100A at a constant 100V I am at a loss ...so I would appreciate a circuit that reveals which components could bring those power sources together to power the motor if it is even possible. Thankyou for your patience I want to learn.

9. ### MrChips Moderator

Oct 2, 2009
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Well it still cannot be done. You are asking for 10KW and you only have sources of 0.1W and 100W.

10. ### thatoneguy AAC Fanatic!

Feb 19, 2009
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You can use a boost converter switching supply for your low voltage/high current output to make it a useful voltage at a lower current.

The static generator is for demonstrations and tricks, no useful power can be drawn from small ones, other than for lighting neon bulb or making hair stand on end.

V x A = Power

In any system, you will not get more power out than you put power in, you'll be very lucky to get 95% of the power in back out.

11. ### crutschow Expert

Mar 14, 2008
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Power is Volts times Amps. And there's no way to get more power out then you put in (of course the over-unity nuts will disagree with that) .

Jun 23, 2011
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Thankyou...Ill look into the boost converters. Had a very close lightning storm on the farm a few yrs back. Got me pondering the static charges ....seems like plenty of amperage and voltage there.. is it that the static charges are so numerous that when the potential between positive and negative(earth) connect they release that mega plasma? Again Im obviously missing a key factor or two.

Jun 23, 2011
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Sorry still very new at this. I dont know if Im sending a message exclusively to "thatoneguy" or the whole community. I like the boost converter idea! After looking into them I see the newer IGBT type is favored by some. Any thoughts? I now better understand the relation ship of E,I and R. I found there are op amp circuits that convert E to I and vice versa. My amperage will be fluctuating on the input. It must be possible to have a steady output of lower amps and the resulting higher voltage.

14. ### thatoneguy AAC Fanatic!

Feb 19, 2009
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You need to get the range of output voltage you are getting at low voltage.

Look at a way to get it to a higher voltage, if it is a generator, add poles, or rearrange them.

15. ### THE_RB AAC Fanatic!

Feb 11, 2008
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There are a lot of good projects on the net for home made wind generators, complete with home-made generators using supermagnets and home made electronics. A quick google should find some.

Regarding your generators, as a general rule it is easier and more efficient to convert a higher voltage to a lower one, so if possible you are better off with a generator design that makes more voltage than you need, and convert the voltage down using a Buck SMPS system (to go to your battery).

Your 1v high current generator is much more difficult to work with, and you might consider rewinding/redesigning it to produce more volts if you want to get a good overall result.