Bandpass active filter no output depending on chip

Thread Starter

po210

Joined Dec 24, 2013
14
The filter shown in the drawing is a 50Hz band pass filter that works perfectly with CA3140 but not with MCP6272/MCP6002/LM358.There is no output at Vo, except if i remove Rr=2K4.Then i see signal output, but not useful because then this is not a bandpass filter...
Other than CA3140 chip not being a dual operational amplifier,I can't see the difference with the others chips.
Power supply is 5.5V for all the tests and in non inverting input I add a 2.5V signal as offset (not shown in drawing).Do you think is something retated with different internal technology for each chip?. What could i try or measure?IMG_20200613_100944.jpg
 

ericgibbs

Joined Jan 29, 2010
10,205
hi po,
Please annotate the circuit components eg: R1 , R2, C1, C2, it will make easier for us to follow.
Also add pin numbers to the OPA.
E
 

Thread Starter

po210

Joined Dec 24, 2013
14
My apologies, ...I tried in another bredboard and it worked.
Pin connections were ok,but your confidence in the answer made me recheck it all.
Thanks!
 
Top