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+5V and -5V OUT PSU Problem !!!!


xsumirx

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Hello,

Actually I am designing a Digital Voltmeter using ICL7107. Having capability to measure 0-200v with 0.1 resolution.

My Problem is, when I connect the output of 7805 and 7905 to ICL7107 at Pin 1 and 26
respectively. the output voltage become zero  at the out pin of 7905 as well as 7805.

and not even a single 7-seg Display showing any output

Please help me  !!!!  :'(

I am not able to Judge weather its the Problem with my PSU or ICL7107.

I have attached my PSU ......  ??? ???

post-77981-14279144449392_thumb.jpg

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All right, you're not trying to do what I thought which was measuring its own power supply.

The first thing which could be wrong is the 7660 isn't needed, as you already have a negative supply, so it needs removing.

Secondly, what's the transformer's voltage rating? The filter capacitor values appear to be too small.

And Finally, have you made all the 0V connections?

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