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.