Where did the op amp ground pin go?

RE: Where did the op amp ground pin go?

james hardy — Sun, 15 May 2016 23:06:36 GMT

Thanks Milan for the tip on 1622. I didn't know about that interesting ampifier.

I learned something and that makes it a good day. A "Gnd" pin is a convenient place for for not only the voltmeter but logic level reference and power supply decoupling too.

Thanks - old jim

RE: Where did the op amp ground pin go?

Soufiane Bendaoud — Tue, 26 Apr 2016 21:51:13 GMT

@Milan, correct. There are "special" cases, look at the OPA1622 for instance.

RE: Where did the op amp ground pin go?

Soufiane Bendaoud — Tue, 26 Apr 2016 21:50:08 GMT

James, I can't disagree that it's misunderstood. I didn't think about the water analogy so thanks for the tip.

RE: Where did the op amp ground pin go?

Milan Jakes — Sun, 24 Apr 2016 14:51:16 GMT

Special GND pin? It could be needed as a refference for compesation capacitor inside the OPAMP. But this capacitor is standardly connected to V- and this is the main cause why +PSRR is larger then -PSRR at higher frequnces and at all OPAMPs. I think that it is good to know this detail when designing very low noise circuits.

RE: Where did the op amp ground pin go?

james hardy — Wed, 06 Apr 2016 15:54:31 GMT

"Ground" is the most misunderstood term in all of EE.

It's just a convenient place to put your voltmeter's black lead and nothing more.

Voltage being potential [bold] difference[/bold] we need always to specify between what two points.

Check out this physics blog i frequent

www.physicsforums.com/.../

"""

I'd like to see the term "ground" disappear because it's so widely misunderstood.

That's partly because of the water analogy we've all heard.

As kids we played in the yard with the garden hose and observed that

1. the water meter is in the ground , and

2. water from the hose falls to the ground and soaks in.

So we're imprinted early that water has some affinity for "Ground" , when it's really just gravity..

We transfer that misconception to electricity..

so try to keep Kirchoff in mind. """""""

It's not gravity that pulls lightning down to the ground.

old jim hardy