Feedback potentiometer circuit QUESTION

In summary, the resistor R25 provides an offset voltage to the pot so that it will go fully positive when the pot is unplugged.
  • #1
fta_25
3
0
Hi I just have a quick question for a feedback potentiometer circuit what is the purpose of the resistor R25? Please see circuit diagram below (attach)

Thx a lot
Fta_25
 

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  • #2
Since V+ = V- that terminal has voltage = Vout. Then you have a voltage divider type of thing with R24 and R25. Also given that the input at V+ has two inputs (two wires) I would say that R24 and R25 are providing some kind of offset voltage.
 
  • #3
thx a lot
fta_25

Since V+ = V- that terminal has voltage = Vout. Then you have a voltage divider type of thing with R24 and R25. Also given that the input at V+ has two inputs (two wires) I would say that R24 and R25 are providing some kind of offset voltage.
 
  • #4
  • #5
thx a lot...=)
 
  • #6
You're welcome, but what about the quiz question?
 
  • #7
hi,

i know it is an old topic but i need a little bit help. I try to made that circuit diagram, my question is where do i connect 0V for supply, and where measurements are taken. I connected yust like circuit above, and measure on pin 1 (V out), and on - 12V pin?,and with 20k pot i get measurements from 18V to min. 7V, i believe that measurements must be taken on pin 1 and ground (0V), to get full scale (i need scale from 0V-10V) but there is no ground in circuit?


need help

regards
 
  • #8
Ground isn't shown, but there is one.

It is where the positive supply's negative terminal and the negative supply's positive terminal are connected.

Incidentally, R25 is present because the potentiometer can be unplugged and this would leave the non inverting input open circuited. This would produce random output, depending on the static charge on this input.

Putting R25 in makes certain that the output goes fully positive if the potentiometer is unplugged.
 
  • #9
thanks for reply but i still can't determine where that should be "It is where the positive supply's negative terminal and the negative supply's positive terminal are connected", could u please mark it on diagram.

thanks
 
  • #10
I have shown the power supply connections and added some changes to the resistor network to give you the 0 to 10 volts. This is approximate and you will need to adjust it later.

[PLAIN]http://dl.dropbox.com/u/4222062/Opamp%20buffer.PNG [Broken]
 
Last edited by a moderator:
  • #11
thanks

regards,

omnikey
 

1. What is a feedback potentiometer circuit?

A feedback potentiometer circuit is an electronic circuit that uses a potentiometer (a variable resistor) to regulate the amount of feedback in a system. It is commonly used in electronic devices to control the output of a system, such as volume control in audio amplifiers.

2. How does a feedback potentiometer circuit work?

A feedback potentiometer circuit works by adjusting the resistance of the potentiometer, which in turn affects the amount of feedback in the system. As the resistance is changed, the feedback is either increased or decreased, which alters the output of the system.

3. What are the components of a feedback potentiometer circuit?

A feedback potentiometer circuit typically consists of a potentiometer, a feedback resistor, and an amplifier. The potentiometer and feedback resistor are connected in series, and the amplifier is connected to the output of the circuit.

4. What are the advantages of using a feedback potentiometer circuit?

One advantage of using a feedback potentiometer circuit is that it allows for precise control of the output of a system. It also provides stability and can help reduce noise in the system.

5. How is a feedback potentiometer circuit different from other types of feedback circuits?

A feedback potentiometer circuit is different from other types of feedback circuits in that it uses a potentiometer to adjust the feedback, rather than a fixed resistor. This allows for more precise control and can result in a more stable system.

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