Valve Crystal Oscillator Grid Current

[John M0GLN]

A bit more research into this topic has revealed that the current flowing through the crystal - and thus through the indicator bulb in series with it - is an r.f. current, not d.c. (Obvious, in retrospect ) Therefore, the d.c. grid current of the oscillator valve is quite a different current altogether. And that explains why it appears that the grid current of the osc. valve appears to be so very and contradictory high when first meeting this technique.

Al.

Still a bit puzzled, why should it make so much difference? The r.f. current is still a current with presumably an RMS value comparable to a dc one, sufficient to light the bulb and perhaps burn out the crystal, the anode will be supplying an r.f current as well which could be of similar magnitude.

John