Part Number: LM741
Figure 1-2 in the Texas Instruments Application Report "Understanding Operational Amplifier Specifications" identifies the resistance between the sig(+) and sig(-) terminals as Ri. So, the value given for the “Input resistance” of 2M (typ) in section 6.5 of the LM741 datasheet is the resistance between the sig(+) and sig(-) terminals, right?
Hi Mike,
Yes, you're correct. The 2 MΩ value listed under "Input resistance" in the LM741 datasheet is indeed the differential input resistance. This is the equivalent resistance measured directly between the non-inverting (+) and inverting (-) input terminals, just as Figure 1-2 illustrates.
You may have already seen this while reading the application report, but in case you haven't, section 5.8 of "Understanding Operational Amplifier Specifications" describes the different parasitic elements on the inputs of an amplifier in more detail.
Best Regards,
Alex Curtis
