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Hi All

I'm trying to make a circuit for a Physics experiment where I measure the voltage output from a thermopile. Because the raw output voltage is in millivolts, I need to use an op-amp circuit to amplify the voltage. The circuit above should amplify it by a factor of 1000, as R1/R2 = 1000.

I connected a voltmeter between the output after R4 and the TP- pin to measure this amplified voltage, but it reads ~0V and doesn't change so I think I have the voltmeter wired to the wrong bits. I know the thermopile works, because I've measured it to output a few millivolts by itself.

I'm new to circuits and have been following diagrams to set this up. Would anyone be able to let me know where the voltmeter should actually be, or if the circuit is wrong?

Thank you

Datasheets:

• LM358
• Thermopile

I'm trying to make a circuit for a physics experiment where I measure the voltage output from a thermopile. 

Because the raw output voltage is in millivolts, I need to use an op-amp circuit to amplify the voltage. The circuit above should amplify it by a factor of 1000, as R1/R2 = 1000.

I connected a voltmeter between the output after R4 and the TP- pin to measure this amplified voltage, but it reads ~0V and doesn't change so I think I have the voltmeter wired to the wrong bits. I know the thermopile works, because I've measured it to output a few millivolts by itself.

I'm new to circuits and have been following diagrams to set this up. Would anyone be able to let me know where the voltmeter should actually be, or if the circuit is wrong?

Datasheets:

• LM358
• Thermopile

Circuit diagram

Hi All

I'm trying to make a circuit for a Physics experiment where I measure the voltage output from a thermopile. Because the raw output voltage is in millivolts, I need to use an op-amp circuit to amplify the voltage. The circuit above should amplify it by a factor of 1000, as R1/R2 = 1000.

I connected a voltmeter between the output after R4 and the TP- pin to measure this amplified voltage, but it reads ~0V and doesn't change so I think I have the voltmeter wired to the wrong bits. I know the thermopile works, because I've measured it to output a few millivolts by itself.

I'm new to circuits and have been following diagrams to set this up. Would anyone be able to let me know where the voltmeter should actually be, or if the circuit is wrong?

Thank you

Datasheets:

• LM358
• Thermopile

Hi All

I'm trying to make a circuit for a Physics experiment where I measure the voltage output from a thermopile. Because the raw output voltage is in millivolts, I need to use an op-amp circuit to amplify the voltage. The circuit above should amplify it by a factor of 1000, as R1/R2 = 1000.

I connected a voltmeter between the output after R4 and the TP- pin to measure this amplified voltage, but it reads ~0V and doesn't change so I think I have the voltmeter wired to the wrong bits. I know the thermopile works, because I've measured it to output a few millivolts by itself.

I'm new to circuits and have been following diagrams to set this up. Would anyone be able to let me know where the voltmeter should actually be, or if the circuit is wrong?

Thank you

Datasheets:

• LM358
• Thermopile

Circuit diagram

Hi All

I'm trying to make a circuit for a Physics experiment where I measure the voltage output from a thermopile. Because the raw output voltage is in millivolts, I need to use an op-amp circuit to amplify the voltage. The circuit above should amplify it by a factor of 1000, as R1/R2 = 1000.

I connected a voltmeter between the output after R4 and the LM358 ground to measure this amplified voltage, but I get a constant voltage of ~1.4V that doesn't change with the thermopile input so I think I have the voltmeter wired to the wrong bits.. I know the thermopile works, because I've measured it to output a few millivolts by itself.

I'm new to circuits and have been following diagrams to set this up. Would anyone be able to let me know where the voltmeter should actually be, or if the circuit is wrong?

Thank you

Datasheets:

• LM358
• Thermopile

Circuit diagram

Hi All

I'm trying to make a circuit for a Physics experiment where I measure the voltage output from a thermopile. Because the raw output voltage is in millivolts, I need to use an op-amp circuit to amplify the voltage. The circuit above should amplify it by a factor of 1000, as R1/R2 = 1000.

I connected a voltmeter between the output after R4 and the TP- pin to measure this amplified voltage, but it reads ~0V and doesn't change so I think I have the voltmeter wired to the wrong bits. I know the thermopile works, because I've measured it to output a few millivolts by itself.

I'm new to circuits and have been following diagrams to set this up. Would anyone be able to let me know where the voltmeter should actually be, or if the circuit is wrong?

Thank you

Datasheets:

• LM358
• Thermopile