Communities

Writing
Writing
Codidact Meta
Codidact Meta
The Great Outdoors
The Great Outdoors
Photography & Video
Photography & Video
Scientific Speculation
Scientific Speculation
Cooking
Cooking
Electrical Engineering
Electrical Engineering
Judaism
Judaism
Languages & Linguistics
Languages & Linguistics
Software Development
Software Development
Mathematics
Mathematics
Christianity
Christianity
Code Golf
Code Golf
Music
Music
Physics
Physics
Linux Systems
Linux Systems
Power Users
Power Users
Tabletop RPGs
Tabletop RPGs
tag:snake search within a tag
answers:0 unanswered questions
user:xxxx search by author id
score:0.5 posts with 0.5+ score
"snake oil" exact phrase
votes:4 posts with 4+ votes
created:<1w created < 1 week ago
post_type:xxxx type of post
Search help
Notifications
Mark all as read See all your notifications »
Q&A

What we call this opamp configuration? [SOLVED]

+0
−2

1- What we call this opamp configuration?
2- What's the advantage and the disadvantage of this circuit?
3- And what's the purpose of the L2 in the feedback?

I have changed gradually the value of L2 from 1 pH to hundreds of H but nothing noticeable, then I replaced it with a resistor and did the same process the result was the same, in the end I replaced them with a wire the result was also the same.

Edit: this circuit was designed in National Aviation University of Kyiv, Ukraine.

The circuit is suposed to exhibits a maximum in-band total harmonic distortion (THD) of 1.7%. And a maximum in-band phase noise of −139.3 dBc/Hz at 100 kHz offset frequency and has an outstanding value of a standard figure of merit (FoM) of −198.6 dBc/Hz.

The mess

Edit2:
For question 3 the inductor L1 provides positive shunt–shunt feedback.

Edit3:

For question 1 the opamp configuration is a Negative inductance circuit, a type of negative impedance converter.

Negative impedance converter

This circuit can be configurated in different ways the negative of any impedance can be produced, including negative capacitance and negative inductance.

Why does this post require moderator attention?
You might want to add some details to your flag.
Why should this post be closed?

3 comment threads

Edit: this circuit was designed in National Aviation University of Kyiv, Ukraine. (1 comment)
Not really solved (2 comments)
No input signal? Therefore, does the circuit produce this output? Oscillation? (2 comments)

1 answer

+1
−1
What we call this opamp configuration?

 

A mess.

What's the advantage and the disadvantage of this circuit?

This can't be judged without the stated objectives. It might be useful for keeping undergrads busy trying to analyze this circuit.

And what's the purpose of the L2 in the feedback?

None the way the circuit is drawn. Ideal opamps have infinite input impedance, meaning no current flows into or out of the inputs. With no current flowing thru it, L2 doesn't "do" anything.

It's hard to guess what went wrong or what was intended, but L2 should be working against some finite impedance, and was probably intended to be in the negative feedback path.

Again, it's impossible to evaluate a circuit without specs for what it's supposed to do. Any inputs and outputs also need to be defined as to what they are supposed to receive or produce.

Why does this post require moderator attention?
You might want to add some details to your flag.

0 comment threads

Sign up to answer this question »

This community is part of the Codidact network. We have other communities too — take a look!

You can also join us in chat!

Want to advertise this community? Use our templates!

Like what we're doing? Support us! Donate