Terminal Glitchiness

It just occurred to me (in the shower, yeah) that maybe you can catch 'em, too.

Does your scope do pattern triggering?

If so, you’re ready!

If not, then some circuit design will be in order.

The video of Sadler in Florida suggested that the cathode (cold) wire from the tube goes to a current sense resistor inside the power supply, with the other side of the resistor grounded. Measuring the voltage across that resistor would provide a nice analog equivalent of the tube current, with a low-pass filter to strip off the supply’s high-frequency hash.

Feed the voltage into a comparator to generate a signal when the current exceeds a specific level, maybe 100 mA, to see only the high-current glitches.

Then set up a logic gate to be high when the Enable signal is high (inactive) and the comparator sees a glitch. Trigger your scope on that, look back in time a few microseconds, and you’ve captured a glitch where none should be.

Engrave a few test patterns at, say, 10% power:

And see what you can see:

Take your mind off all your old problems, it will … :grin: