5.3.4
Quench gaps
A special form of static gap is known as the quench gap. In this gap
the electrodes are wide flat plates with their faces parallel and
spaced very close. The electrodes are spaced from each other with
mica rings that enclose the gap area. The gap areas between electrodes
become sealed chambers and the oxygen in these chambers is used up
quickly when the gap is first put into operation. This type of gap
works fairly well at lower voltages than other gaps and provide
a nearly continous wave (CW) output. These were used in spark radio transmitters
until spark transmitters became obsolete with the invention of the triode
vacuum tube in the 1910s. This gap design is difficult to implement
due to the sealed nature of the gaps and lack of suitable material
for the spacers. The mica rings normally used are difficult to find
and expensive.