741 Op Amp not working as expected

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darrough

Joined Jan 18, 2015
86
I found the following circuit in "Make: Analog Synthesizers" by Ray Wilson. The book says that this configuration should amplify the input by a factor of 11. In fact the output is about 1/3 of the input. It seems like the chip is not giving any output at all. I tried a couple different chips and they all seem to have the same results.

For this particular IC, 2 is inverting in, 3 is non inverting in and 6 is output.

Do I need to provide a current limiting resistor for the supply?
 

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RamaD

Joined Dec 4, 2009
328
The connections are interchanged. Make the connections as below.

Also, the output will be limited to a max. of +5V and -5V even on a rail to rail opamp. This will be specified in the datasheet. For 741, it would be much less. Assuming +/-2.5V output swing, max input should be 2.5/11, about +/-225mV.
 

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AnalogKid

Joined Aug 1, 2013
12,135
In the original schematic you need to reverse pins 2 and 3. Also, 2 x 11 = 22, which is much greater than your 10V power supplies, so the circuit will clip and distort. Also, note that a 741 output stage cannot swing rail-t0-rail, so the max output swing with +/-5 supplies is only about +/-3V.

ak
 
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