capacitance load of oscilloscope probes

That sounds like that should work fine.

Jon

Thanks. I was reading a bit more about probes and realized that the variable capacitor on the probe is used to cancel the scope's input capacitance. Hence the former should have the latter within its range. However, that leaves us with the probe's own capacitance. In this case, it is 90pF/20pF (for 1:1/1:10 attenuation). Are these values typical for probes for 60 MHz scopes?

Yes, pretty typical. At 1:1 attenuation, the probe is basically just a length of coax cable, and the capacitance of those is always pretty high, tens of pF per foot for even the best. 20 pF for a standard X10 probe is about normal, some really high-end Tektronix probes with 400 MHz bandwidth that cost $400 each about 20 years ago, are 14 pF.

If you need lower capacitance, you have to go to amplified probes, and those cost several thousand $.

Jon

Okay, thanks for the explanations.

One more point I just was wondering about. Is it typical that probes for different bandwidths have same capacitance? e.g. should a 60 MHz probe have the same capacitance as a 200 MHz probe? I am suspecting that higher frequency probes are going to have lower capacitance else higher freqs are going to be attenuated more. But I could be wrong, because based on your explanation, at 1:1 all probes are going to have the same capacity.

Many good o'scope and probe tech and learning pdf's at the following including Tektronix ABC's of probes:

You won't find high-frequency, high-impedance passive probes with 1:1 attenuation. It just can't be done. The higher-frequency probes with

Jon