The LG200 is a German military helium thyratron from the 1940's. The upper frequency limit is 150 kHz. It was used in FuG 218 Neptun low-to-mid-VHF band airborne intercept radar systems.
The thyratron is the switch that connects the power to the transmitting valve pulse by pulse. The pulse power was 1 kW.
The screen hides the inner detail. Following the heater connections shows that the cathode is in the centre.
On the lower left are the heater connections.
The metal top has a threaded hole into which would be fitted a knob (SeeRV12P2000 for an example) to allow valve changes from the front panel. The base pins are equi-spaced around a circle and location is given by the glass key moulded into the envelope. Seen here at the top of the image.
The eight base pins. The heater connections can be seen and the pip between them identifies pins 1 and 8.
The wide glass tube envelope is 30 mm in diameter and, excluding the base pins, is 54 mm tall.
Reference: Data-sheet. Type LG200 was first introduced in 1942. See also1942 adverts.
