MOTM

Bruce,

I've seen this too - I believe it's just laziness on the designers part.
(MOTM schemo's always show the power connections.)  I think it's fair to
assume that there is power connected.  However, I don't think it's fair to
assume that a bi-polar power supply is used!  I believe that some op amps
can be operated with a single polarity (usually positive) and ground.

Cheers,
George
----- Original Message -----
From: <bruce@...>
To: <motm@yahoogroups.com>
Sent: Friday, June 15, 2001 6:14 PM
Subject: [motm] OT - Daffy OpAmps / Where's my power?


Ok, off topic question about schematics and Op Amps.

I have seen a lot of schematics that involve Op Amps, yes they seem to
make the world go 'round.  I am no expert on schematics. but one thing
is troubling me.

I see these lovely OpAmps connected with the + input, - input and the
output.  Many times I don't see any other connections.  Now I am
pretty sure that these things take V+ and V- (to the chip) to make
them run, but they don't show on the schematics.

Are these connections just assumed?  Or are there real ways to use
OpAmps with just the 2 inputs and the output with no power applied?

Thanks in advance for the answers.

Bruce




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