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Thread

OT - Daffy OpAmps / Where's my power?

2001-06-15 by bruce@sigalarm.com

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

Re: [motm] OT - Daffy OpAmps / Where's my power?

2001-06-15 by Paul Schreiber

Connections assumed! Also, this is par for the course for digital schematics
as well. I *hate* this practice.
Note the MOTM schematics *always* show the power.

Paul S.

----- Original Message -----

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From: <bruce@...>
To: <motm@yahoogroups.com>
Sent: Friday, June 15, 2001 5:14 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
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>

Re: [motm] OT - Daffy OpAmps / Where's my power?

2001-06-15 by George Kisslak

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

Show quoted textHide quoted text

----- 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

Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/

RE: [motm] OT - Daffy OpAmps / Where's my power?

2001-06-15 by Tony Karavidas

It's not laziness, it's preference. It has to do with clutter. A page full
of op-amps becomes very cluttered with power pin info, and that can detract
from communicating the intent of the design. With op-amps, there is almost
always feedback components drawn around the opamp, and having to go around
the power pins makes it more messy. I like to keep the op-amps free of power
pins, but somewhere else on the schematic I show a power block for each one.
To me, it's the best of both worlds. But that's MY preference. :)

Tony Karavidas
Encore Electronics

http://www.EncoreElectronics.com

Designers of "The best MIDI to CV converter on the planet." -Keyboard Oct.
1997

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> -----Original Message-----
> From: George Kisslak [mailto:groovyshaman@...]
> Sent: Friday, June 15, 2001 3:44 PM
> To: motm@yahoogroups.com
> Subject: Re: [motm] OT - Daffy OpAmps / Where's my power?
>
>
> 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
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
>