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Isolated Power source

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amitak

New Member
Hi,
My i use a 12V smps as an input to a variable power supply to vary output from 2V to 10 V
I would like the circuit to display current and voltage
I purchased the voltmeter and ammeter - the ready made ones working with 5 volt supply
I use another 5 volt regulator taking input from the same 12 v source to power up the voltage displaty.
Every thing works fine with the voltmeter, but the ammeter circuit shorts my output voltage to ground, i guess that because the 5 vv rehulator shares a common ground with the main variable regulator.
So i feel that i need an isolated voltage supply, can i do it without extra regulator simply using diodes and capacitors or some other simple way.
any suggestions ?
 

amitak

New Member
yes i am connecting ammeter in series ..
and it works fine if i power it from a different 5 volt power supply
 

dougy83

Well-Known Member
Try putting the ammeter in line with the return path (negative lead) of the power supply, that way the common ground is meant to be there.

If you want to have it on the positive lead, you will need a floating supply (or at least one that is higher than the output voltage.
 

amitak

New Member
yes .. wow .. thank you very much ..beautiful idea ..
i am fine placing it anywhere as long as it reads the current ..
i donot need to complicate things making the isolated supply at all ..
brilliant solution .. my problem is solved..
thanks again.
 

dougy83

Well-Known Member
Perhaps you should give more specifics.

If you are after instruction on how to make an isolated power supply, you should start a new thread.

If you want the circuit for the isolated power supply mentioned in this thread, you will find that the OP did not use one in the end.
 
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