Quote:
Originally Posted by wa2ise
Many sets drove the CRT cathode, and one way to work around the capacitance from the cathode to the heater would be to introduce some inductance in the heater supply...
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Oops, you're right. Nearly all sets do. Why do I keep forgetting that?
I also keep forgetting that the grid is a fairly large massive structure. The G1 to other electrodes capacitance for an 12LP4 is 6 pF. For the cathode it's 5 pF. I wonder if they don't include the heater in that rating?
At 20 MHZ that's a reactive load of about 1,600 ohms. Not too hard to drive.
John