General Electric KR-7 and KR-9A Kenotrons

Ref. G10

The KR-7 oil-immersed kenotron of the fifties is 7.5”(18.5 cm) long with a maximum diameter of about 3.5”(9 cm), made of clear glass, with a peculiar shape probably intended to assure a large contact area with the surrounding oil for better heat dissipation.

The anode is the dark metal dome on the left side of the picture, extending partly inside the glass housing as is perfectly visible on the X-rays, and is centered by an axial filament on a helical support.

Technical specifications are not available.

A descendent of this KR-7 kenotron, the KR-9A is of about the same size and shape, and is made of frosted glass, with much more of the anode dome inside the glass housing and a somewhat different filament.