Tunnel Diode Burnout from the Video Transient of Gaseous Noise Sources (Correspondence)

The helix-coupled, coaxial, gaseous noise source poses a burnout hazard to tunnel diodes unless certain precautions are taken. The attached oscillograms illustrate the transient in question. Typical short-circuit peak currents are 300 ma. The transient is a consequence of the sudden forced transition of the helix core from a nonconducting, unionized gaseous media to that of a conducting plasma. The transient coupled to the helix is easily suppressed with a high-pass or band-pass filter, or even by adequate padding. If only a pad is used, a word of warning is in order. The pad must be of the type that attenuates video, as well as radio, frequency.