09-02-2021, 05:54 PM
Though even if you accept x1,000 attenuation, and use a 47kΩ resistor and 50Ω coax and termination, you still load the circuit under test with that 47kΩ, which will affect the Q and characteristics. IFT is meant for driving into a open-circuit grid, after all.
It's a good technique, just not applicable here.
Amie's x10 probe with 1MΩ loading (or 10MΩ ? as most x10 probes are) is more suitable in this scenario. Yes, there's capacitance, but that can be allowed for by reduction in trimmer.
Or, (better), a JFET source-follower powered by local 9V battery, the JFET gate lead tacked directly onto the Circuit Under Test. And then you really can have 4.7k and 50Ω to the scope!
It's a good technique, just not applicable here.
Amie's x10 probe with 1MΩ loading (or 10MΩ ? as most x10 probes are) is more suitable in this scenario. Yes, there's capacitance, but that can be allowed for by reduction in trimmer.
Or, (better), a JFET source-follower powered by local 9V battery, the JFET gate lead tacked directly onto the Circuit Under Test. And then you really can have 4.7k and 50Ω to the scope!
