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Hello Paul,
this test circuit with open R3 and R4 can never work. Even an offset voltage of 1uV would keep the opamp close to one of the power supply rails.
Do you seriously believe that? I don't! More likely you can put 10 camels through the eye of a needle than this theory above is true.
Best regards, Helmut
Are you using the "typical" input offset voltage Helmut? What if you use the minimum? Typical offset for NTE937M is 3mV. So I'd bet my offset is about 1mV or less.
The circuit used to have the offset resisters and adjustable pot, but I had to remove those because they caused a lot of noise. I know that some pots can generate a ton of noise. When the offset parts were removed most of the noise went away.
You should note that the noise is random, which caused the signal to reach both positive and negative saturations. I could watch the signal drifting all over the place over time. Some times the signal was in saturation and sometimes it was not saturated. That provided plenty of time to study the signals typical swing per second. :-)
Actually I do. :) Consider the radiation resistance of a yagi antenna. It's not uncommon to have 1"+ diameter poles, so electrical resistance is insignificant, but the radiation resistance is typically designed for 50 ohms, but can be extremely high ... in the thousands of ohms. This is resistance, not reactance. Where would such 50 ohms noise come from Helmut? There is no radiation resistance noise. :-)
Think about it. If there's no di/dt then there's no field. If there's no field then there can't be any such noise coming from the field. When there is di/dt there's still no radiation noise, lol. Where are you proposing this magical radiation noise is coming from Helmut? Perhaps on a quantum level there might be some yocto zero point energy noise, lol.
Paul
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