Two floating LM7805 in series.

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tyfon1

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Hi there!

I know that for negative supplies a LM79xx is needed. As I don't have any of those I was thinking to
connect two LM7805 outputs in Series. Each one powered by a separate battery. This should then be similar to two bench power supplies with floating outputs connected in series.
It should be possible to have -5 - 5V or 0-10V supply. Is my thinking correct? And if not, what is the problem and why does it work with bench supplies?

Thank you

Tyfon1
 

Hi,
If you have isolated power inputs to each 7805 [ your batteries] you can use 2, 7805's for a dual supply.
E
 

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Why do you need a dual-polarity power supply?
ANY AC opamp circuit will work with a single supply voltage if its (+) input is biased at about half the supply voltage and the signal input, output and feedback to ground parts are capacitor-coupled.
Here is an example:
 

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