I built this with a simple breadboard and using the following op-amp:
http://en.wikipedia.org/wiki/File:Op-Amp_Non-Inverting_Amplifier.svg
OPA244:
http://www.farnell.com/datasheets/9250.pdf
The supply is 12V regulated and V- is connected to ground.
The resistors are R2=10k and R1=100.
Vin is generated with a function generator, frequency is a few Hz.
With Vin = 50mV I get about 2V for Vout (measured with oscilloscope)
Gain 40
With Vin = 200mV I get about 6V for Vout
Gain 30
Naturally I should be getting a gain of 101. I've tried two different op-amps and get the same value.
I've also tried with a 1k resistor instead of the 10k. Here the gain varied between 3 and 2 instead of 11.
Any idea what could be going wrong? Is the op-amp not suited for my application?
Edit:
Seems like I jumped the gone on this. For a single supply op-amp r1 should not be connected to ground but to V+/2?
http://www.eng.yale.edu/ee-labs/morse/compo/sloa058.pdf
So I just use a voltage divider with like 2 10k resistors from my source to get this and everything will be fine? I'll try tomorrow at least.
http://en.wikipedia.org/wiki/File:Op-Amp_Non-Inverting_Amplifier.svg
OPA244:
http://www.farnell.com/datasheets/9250.pdf
The supply is 12V regulated and V- is connected to ground.
The resistors are R2=10k and R1=100.
Vin is generated with a function generator, frequency is a few Hz.
With Vin = 50mV I get about 2V for Vout (measured with oscilloscope)
Gain 40
With Vin = 200mV I get about 6V for Vout
Gain 30
Naturally I should be getting a gain of 101. I've tried two different op-amps and get the same value.
I've also tried with a 1k resistor instead of the 10k. Here the gain varied between 3 and 2 instead of 11.
Any idea what could be going wrong? Is the op-amp not suited for my application?
Edit:
Seems like I jumped the gone on this. For a single supply op-amp r1 should not be connected to ground but to V+/2?
http://www.eng.yale.edu/ee-labs/morse/compo/sloa058.pdf
So I just use a voltage divider with like 2 10k resistors from my source to get this and everything will be fine? I'll try tomorrow at least.
Last edited: