Why isn't this amplifier amplifying?

Thread Starter

dsharp02

Joined Aug 8, 2015
17
So I was playing around with an oscillator circuit and RC filters to try and make a sine wave generator. I succeeded in getting what appears to be a pretty decent sine wave, but after filtering the amplitude has dropped from 12v peak-to-peak to 0.5 volts peak-to-peak. So tried to setup a non-inverting amplifier with a gain of 2, using an op-amp. However for some reason the output from the op-amp is a steady 11.2v.

What am I missing here?

Thanks,
Dave

Capture.PNG
 

Jony130

Joined Feb 17, 2009
5,123
Upload a LTspice file.
Notes that the voltage at non-inverting amplifier input contains some DC-offset around 6V, and this DC voltage is also amplified by your opamp. So we need to add a voltage divider and the capacitor at non-inverting input and a capacitor in series with R9.
See the example
58.jpg
 
Last edited:
Top