Can someone decipher the circuit attached. What will the voltage be at pin 2. Output at pin 6?? is current getting amplified here?

 

The circuit will try to make the voltage at pin 2 equal to the voltage at pin 3. that would be ground. That drawing is probably the worst hot mess I have ever seen. What is getting amplified is the voltage difference (pin3 - pin 2)

 

Where did you get that schematic???

 

Where did you get that schematic???

Hot Mess: 2 Schematic: 1

 

Can someone decipher the circuit attached.

No. That has to be one of the most chaotic, messiest schematic diagrams I've ever seen. If you expect anyone to make a serious attempt at answering your questions, re-draw it NEATLY without running wires to and fro all over the place.

That said, I doubt this circuit will do much of anything at all given the screwball way you've got the 741's balance pins connected.

 

Hot Mess: 3 Schematic: 1

 

You really, really need to take a course in how to draw proper schematics.

 

Regarding drawing readable schematics, the attached is a good guide.

 

I think the problem with the wires all over the place on the schematic is because it was drawn with Multisim.
I tidied up the schematic and pointed out the problem with the input offset voltage adjustment pin.

 

And then there's that whole Q11 thing ...

 

I think the problem with the wires all over the place on the schematic is because it was drawn with Multisim.

What does Multisim have to do with it?
You can draw a crappy schematic with just about any schematic program.

 

You are right Carl, but I do not know why is so frequent seeing such awful schematics prepared with that software.

I use Corel Draw and patience. Not much time anyway.

 

I think the problem with the wires all over the place on the schematic is because it was drawn with Multisim.
I tidied up the schematic and pointed out the problem with the input offset voltage adjustment pin.

Thank you so much for correcting.

The circuit will try to make the voltage at pin 2 equal to the voltage at pin 3. that would be ground. That drawing is probably the worst hot mess I have ever seen. What is getting amplified if the voltabe difference (pin3 - pin 2)

Thank you for your reply. I'm seeing a constant 0.7v at pin 2 while the pot is varying voltage from 0-6V.

 

https://www.ti.com/lit/ds/symlink/lm741.pdf pg.7 chp.7.2
if you alter the input bias current from output (in the wrong way) ...
https://www.ti.com/lit/ds/slos094g/slos094g.pdf pg.12 chp.8.1
... then you partially "choke" the input shoulders ... one (more than the other)

if you reduce the vertical differential input amplifier's current -- such may result in

• elevated DC sensitivity (at the "right" circumstances -- more susceptible to oscillations)
• lower GBW (frequency response)
• reduced output SR (slew rate)

the Detailed Model of LM741 Operational Amplifier - YouSpice could be more adequate than the ?unknown response? Multisim variant

 

? insane

 

The inputs and outputs of a lousy old 741 opamp do not work properly when they are within a few volts from ground or the supply voltage.

 

I think the problem with the wires all over the place on the schematic is because it was drawn with Multisim.
I tidied up the schematic and pointed out the problem with the input offset voltage adjustment pin.

There is a mistake in the schematic. The input offset voltage adj pin is connected to pin no.4. But sill the input does not vary and remain stuck at 0.7V.

 

https://www.ti.com/lit/ds/symlink/lm741.pdf pg.7 chp.7.2
if you alter the input bias current from output (in the wrong way) ...
https://www.ti.com/lit/ds/slos094g/slos094g.pdf pg.12 chp.8.1
... then you partially "choke" the input shoulders ... one (more than the other)

if you reduce the vertical differential input amplifier's current -- such may result in

• elevated DC sensitivity (at the "right" circumstances -- more susceptible to oscillations)
• lower GBW (frequency response)
• reduced output SR (slew rate)

the Detailed Model of LM741 Operational Amplifier - YouSpice could be more adequate than the ?unknown response? Multisim variant

Thank you for your response. I've assembled the circuit and the actual input reading on pin no. 2 is constant 0.7V

 

Sorry 10k is connected between pin 1 and 5. Ok, I'm getting input voltage variation from 0.7-2.7v and output from 6-9.7mV Indeed to change or vary the input from 0.05-0.7mV and o/p from 5.6-6.0mV. what should I change in the circuit?

 

? insane
View attachment 209540

This is the circuit I'm working on....Can you explain how does this circuit work... I/p of the op amp at pin 2 varies from 0.05-0.6V and o/p varies from 5.6mV-6mV at pin 6. What is the output of the transistor??