Is My Op Amp Burned Out? Voltage Check

AI Thread Summary
The output voltage of the op amp exceeds the power supply voltage, raising concerns about potential burnout. Users suggest checking the configuration of the power supply and ensuring the voltmeter is correctly connected to the output. There are indications that the circuit design, particularly the use of a 100MΩ feedback resistor with a 0.22μF capacitor, may lead to instability due to a long time constant. The importance of proper grounding and the relationship between the output and input voltages is emphasized. Overall, the circuit's setup and component values are critical to diagnosing the issue effectively.
bphui
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The output voltage of op amp is greater than the power supply voltage (+/- 5V). Is Op amp burned out?
 
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Probably. Have you tried replacing it?
Is it of the order of one of your input voltages?
Is your volt-meter or sensor hooked up to v out and not to your inputs?
Do you possibly have it set up as +10/0V as opposed to +/-5V?
 
BiGyElLoWhAt said:
Probably. Have you tried replacing it?
Is it of the order of one of your input voltages?
Is your volt-meter or sensor hooked up to v out and not to your inputs?
Do you possibly have it set up as +10/0V as opposed to +/-5V?
Yes, I have replaced it and the result is still the same.
I also set the power supply to +5/0V, the output has negative voltage too.
I am connecting charge amplifier with pvdf film.
 
What are you referencing as ground on your voltmeter? Is it the ground off of the power supply?
 
Also, check the difference between your high and ground with a voltmeter.
 
BiGyElLoWhAt said:
What are you referencing as ground on your voltmeter? Is it the ground off of the power supply?
Ground the negative terminal of op amp.
 
bphui said:
The output voltage of op amp is greater than the power supply voltage (+/- 5V). Is Op amp burned out?
What other voltage is connected to the output. The output of the circuit cannot be outside of the power rails without some other power source pulling that point up.

Can you post your schematic?
 
If the negative lead of the voltmeter is hooked to the negative supply when using a split supply setup I can see why you could get readings like this.
 
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berkeman said:
What other voltage is connected to the output. The output of the circuit cannot be outside of the power rails without some other power source pulling that point up.

Can you post your schematic?
This is the circuit.
 

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  • #10
Your schematic does not show which pins you use to connect to the power supply.
 
  • #11
p
Svein said:
Your schematic does not show which pins you use to connect to the power supply.
pin 4 connect to -5v
pin 7 connect to +5v
 
  • #12
Using 100MΩ feedback with a 0.22μF input capacitor is a recipe for trouble. The time constant is 22 seconds - so it will take forever to stabilize.
 
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  • #13
Svein said:
Using 100MΩ feedback with a 0.22μF input capacitor is a recipe for trouble. The time constant is 22 seconds - so it will take forever to stabilize.
I noticed this too. The whole things looks a bit odd. Wondering what is connected to the header?
 
  • #14
Averagesupernova said:
I noticed this too. The whole things looks a bit odd. Wondering what is connected to the header?
The header connects with pvdf film.
 
  • #15
Svein said:
Using 100MΩ feedback with a 0.22μF input capacitor is a recipe for trouble. The time constant is 22 seconds - so it will take forever to stabilize.
Is 100M feedback with 0.22uF and 1000pF?
 
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