Hello Dave,
Yes, he said he could simply vary the gas production changing or the Dc voltage or the gated pulses... In his circuit there is a segment where it receive a logic signal from the pressure sensor, so when the pressure reach a certain value the circuit simply turn off, until the gas is demanded.
wfchobby,
I have a circuit similar to what meyer patented, where i can control the pulses sent to the pll. so i can vary the duty cycle 0-100% and frequency of the gate, i also have a variac, so i can vary the input pulses voltage..