Univerity question - how does this circuit work

Thread Starter

Zsolt8644

Joined Oct 25, 2022
5
Hi!

I am a University student, and I have got a task, to imagine, how this circuit works, what does it do.

The second question is, what parameters should manipulate to change the output the appropriate way.

I am a bit lost.. what doest it do? How does it work?

I would really appreciate if somebody could tell me some info about it.

Thank you in advance!
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Thread Starter

Zsolt8644

Joined Oct 25, 2022
5
hi Z,
Please post your best effort in answering how the circuit works, then we can help you.
E
So, my task is to find out, what does this circuit do, and with parameters can you change to modify an output parameter (which depends on what the circuit purpose)

As Bertus wrote, it can be a tone control circuit. Thank you for your answer.

The three potmeters are to modify the amplify of a frequency band? Am I right?
If you have time and I don't ask too much, please explain me the working method, I'd like really to understand it.

Thank you!
 

MrChips

Joined Oct 2, 2009
27,679
Experienced electronics designers can look at the whole circuit and tell you what it does. When you lack that knowledge and experience you need to look at individual parts of the circuit.

What do R7 and R8 do?
R3?
C10 and R1?
C9?
R1, R2, U5A?
C7?
 

Ian0

Joined Aug 7, 2020
6,698
Hello,

Lookup baxandall tone control.

Bertus
Definitely a 3-band Baxandall tone control - there is a good explanation in Doug Self's "Small Signal Audio" book. ISBN 978-0367468958
I have a copy of Baxendall's original paper if you are interested, but it is designed around pentode valves.
 

WBahn

Joined Mar 31, 2012
27,875
Let's keep in mind that the apparent intent of the assignment is for YOU to apply what you have learned to the examination and analysis of these circuits. It is NOT for you to go out to the Internet and find someone to do that for you.
 

Ian0

Joined Aug 7, 2020
6,698
If you take the C3-C4-R6 and R4-R5-C2 network then what letter of they alphabet does the shape of them suggest? and there's a pair of them. Perhaps Twins?
 

Thread Starter

Zsolt8644

Joined Oct 25, 2022
5
Let's keep in mind that the apparent intent of the assignment is for YOU to apply what you have learned to the examination and analysis of these circuits. It is NOT for you to go out to the Internet and find someone to do that for you.
You are right, however with your help I could run simulations and learnt a lot. Thank you for your point and thanks to everybody who has suggestion according the circuits. There are tons of youtube vids, and the google is my best friend because I know what shall I search for.
 

Ian0

Joined Aug 7, 2020
6,698
You are right, however with your help I could run simulations and learnt a lot. Thank you for your point and thanks to everybody who has suggestion according the circuits. There are tons of youtube vids, and the google is my best friend because I know what shall I search for.
Google isn't quite your best friend because it never tells you the credibility of the sources! A good text book might be a better friend. Have you heard of Horovitz and Hill?
 

Thread Starter

Zsolt8644

Joined Oct 25, 2022
5
Google isn't quite your best friend because it never tells you the credibility of the sources! A good text book might be a better friend. Have you heard of Horovitz and Hill?
No, unfortunately I have never heard about it, yet... but I'm on it! Thank you!
 

dcbingaman

Joined Jun 30, 2021
798
Notice the high and low pass filtering caused by C3,C4 R6 and R4, R5 and C2. Also keep in mind this network causes a phase shift to the signal being fed back that depends upon the frequency. Do you see the feedback path from Q2 to Q1? Notice that if the signal was fed back directly it would be negative feedback and thus nothing interesting would happen but at a specific frequency the T and Pi filters cause a 180 degree phase shift causing positive feedback. I would recommend performing an AC analysis of those networks. It is an oscillator but why it oscillates is the million dollar question.
 
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