Can't get a TLC272IP OP-AMP to work. what am I doing wrong? Answered
I received this week a few TLC272IP op-amp and I wanted to test them.
I created a circuit on a breadboard which looks like the attached image
From what I read on the net, this is a typical non inverting amplifier schema where gain should be (1 + R2/R1)
I connected PIN 3 of the TLC272 to pin 3 of my arduino uno and using PWM I set the output to roughly 1V ("analogWrite(3, 51);")
I used my voltmeter to read the voltage between ground and pin 3 and I could really see 1V
given I used R1 = R2 = 47k, I was expecting to have a gain of x2 and thus read voltage of 2V between pin 1 of the op-amp and ground
I get something that is very unstable, below 1V.
I tried with 4 different TLC272IP I just got and get the same behavior.
am I doing something wrong there? what do I miss? or do I need to review how op-amp are really working?
(I purchased the TLC272IP because it's supposedly single power supply)
thanks for any hint.
PS. in some doc i read that I should not let the second op-amp in the air, so i tried as well by connecting pin 5 to ground and shorting 6 and 7 with a wire or a small 100k resistor but this did not change anything.