What happens if you put a high value resistor (>1MR) across the inputs ? If=
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you try some lower values, what is the least resistance you can put across=
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the inputs before it stops this behaviour ?

Dom

-----Original Message-----=20
From: Richard R. Pope
Sent: Saturday, May 3, 2014 9:22 AM
To: Microcontroller discussion list - Public.
Subject: Re: [EE]:[OT] Could I Get Help with a voltmeter?

Hello All,
     I am trying to build a voltmeter using the ICL7107 ADC chip. Here
is the URL of the schematic that I am using. I did not use the circuit
on the left side that controls the individual LEDs. I am using a ICL7660
DC-DC converter to generate the -5 volts. I can adjust the reference
voltage to 100 mv and the display initializes on start up and then it
shows 1 or -1 with a flashing - sign. If I press the test switch the
display shows -1888 like it is supposed to. If I ground the + lead the
display almost goes to zero. When I disconnect the plus lead and leave
it floating the display slowly climbs in value until it overflows. I
know that this is an important clue but I can't find the problem.
     I have also tried three different circuits including the one that
is in the datasheet and I have tried two different chips. The + and - 5
volts are ok, the ground is good, and the clock frequency is 66KHz.
Could someone please help me?
Thanks,
rich!
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.