Indirectly, this the rationale for using hydrogen/deuterium as fill gas in HV, high power thyratrons. The lower mass/charge ion has less of a tendency to blow hell out of the large area, high emissivity cathode surfaces needed for a good high power thyratron. Xenon, neon, and mercury fills are used for lower operating voltages.
There are cases of cathode stripping during start-up of receiving tubes where the Heaters are "floating" on a DC voltage derived from the B+...
The damage occurs due to the Heater to Cathode voltage is greatly exceed for a short time before the B+ pulls down to it's loaded state.... Very repeatable....you can hear the clicking sound of the arc..
Simple fix is to put a protection zener on the voltage divider ...this way the zener clamps only during start-up, preventing an over-voltage on the Heater...
Problem 100% solved ...
The damage occurs due to the Heater to Cathode voltage is greatly exceed for a short time before the B+ pulls down to it's loaded state.... Very repeatable....you can hear the clicking sound of the arc..
Simple fix is to put a protection zener on the voltage divider ...this way the zener clamps only during start-up, preventing an over-voltage on the Heater...
Problem 100% solved ...
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To point out, here is an article called Kindness to Filaments by John Harper.
http://www.john-a-harper.com/FilamentHeating/index.html
To be kind to the heaters, he suggests doubling the heater supply voltage,
but a resistor is connected in series with the heaters.
The value of the series resistor is the same as a warmer up heater.
.
http://www.john-a-harper.com/FilamentHeating/index.html
To be kind to the heaters, he suggests doubling the heater supply voltage,
but a resistor is connected in series with the heaters.
The value of the series resistor is the same as a warmer up heater.
.
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Normal AC heater supply is sufficiently kind for most purposes, as the transformer resistance limits surge current.
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