741 cross-over distortion

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Frosty_47

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Dear Komrades,

There seems to be some cross-over distortion present at the output from my 741 at very low frequencies ( 6Hz ). Basically I have a simple integrator circuit with a 10uF input capacitor and a 260Ω feedback resistor. The crossover distortion was very bad when I used smaller capacitor and larger feedback resistor. With larger cap and smaller resistor the distortion is barely noticeable but it is still there. I suspect that the poorly designed class AB amplifier inside the 741 is the cause. I would like to know what I could do to eliminate this problem.


Thanks
 
The lousy old 741 opamp is 40 years old this year. It is noisy, has a full output frequency response to only 9kHz and has distortion.

TL07x opamps are much better. They have low noise, wide bandwidth (100kHz) and low distortion (0.003%).

The new LM4562 dual opamp has only 0.00003% distortion.

None of these opamps can drive a load as low as 260 ohms.
Please post your schematic.
 
Can you post a schematic? The circuit you described sounds like a differentiator, not an integrator.
 
Hi,

Yes, it sounds like a diff not an integrator.

Also, some of the older op amps do better with a load to ground like
a 10k or maybe 1k resistor. The LM358 is famous for requiring a 10k
to ground to help keep distortion lower. Try a resistor to ground to
help, but as others have said, a better op amp is the real key, if
that is possible of course.
 
Thank you all for the quick reply. I apologies for the long delay in my reply. At the moment and very little time in school due to unusual amount of lab work involved. Further I made a mistake by calling this circuit an "integrator" when it is actually a "differentiator" op-amp. Below you can see the schematic diagram.

**broken link removed**
 

Thank you for your suggestion. Here is my simple schematic:

**broken link removed**

Perhaps I can use a smaller cap and larger resistor and hopefuly not encounter any cross-over distortion with the above mentioned op-amps.
 
The values of both 260 ohm resistors is far too low. Use 2k ohms minimum so that the opamp doesn't current-limit.
 
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