floating ground, virtual ground how it created in this circuit of M890G multimeter

Hello everybody,

i am attaching M890G multimeter circuit from web i found . in this circuit how the ground is created pls any body can explain.
i have tried to measurement circuits with 7106 ic but there should two power supplies we need one for measuring circuit and onother
display circuit of 7106.

but in this a common ground is created pls any body can explain.

regards
svn

joshua.svn said:

i am attaching M890G multimeter circuit from web i found . in this circuit how the ground is created pls any body can explain.
i have tried to measurement circuits with 7106 ic but there should two power supplies we need one for measuring circuit and onother
display circuit of 7106.

Click to expand...

Your premise is entirely incorrect - the circuit inside the meter is part of the meter, and MUST have a common ground in order to work.

Your confusion is when building a 7106 inside a project, where it may well require a separate supply and ground - in this case though it's all one circuit, and must be powered together.

Are you asking how to attach a meter to a supply so it can measure a voltage from that supply without having a separate supply of its own? A typical example would be a panel meter that does not have a separate supply in a variable voltage bench supply. If that is the case, the solution to the common ground is to generate a negative voltage for the meter , such as with a 7660 voltage converter.

John

Edit: Here's a link to an Intersil application note that addresses the issue: https://www.intersil.com/content/dam/intersil/documents/an96/an9609.pdf

There is some useful info in DMS-AN2 here: https://www.murata-ps.com/en/application-notes/digital-panel-meter-application-notes.html