The MT5545 is a Xenon filled Thyratron with reliable operation over a wide temperature range and is the big brother of the 5544 with double the current capacity.
The design use is for speed control of DC motors. Also specified for counting and sorting devices and electronic switching machines.
The filament needs 60 seconds heating time. The Thyratron is a pulse device and the anode volts and current are limiting values the average current is limited to 6.4 Amps. When conducting the forward voltage drop is 16 Volts. The grid can go negative by a maximum of 250 volts. The deionisation time is 500 μ seconds.
The locating pip for the bayonet holder is on the right. The darkened glass obscures most of the details but the pins from the glass foot are straight with the struts from the electrode assembly bent to fit and welded to the sides of the pin extensions.
The anode end, the twisted anode wire is encased in a glass tube to ensure that the discharge occurs only where it is intended to.
The wide glass tube envelope is 64 mm in diameter, and excluding the 4 special base pins, is 185 mm tall.
Reference: Datasheet. Type MT5545 was first introduced in 1952.