The BT69 is a Thyratron with mercury vapour as the working gas.
The BT69 is used as a switch to apply high current pulses to subsequent equipment. This exhibit was used in induction heating equipment with a TSY5-3000 as a self excited power oscillator.
The BT69 it is designed for a peak anode voltage of 15,000 Volts and can withstand a reverse voltage spike of 15,000 Volts also. The average anode current can be 12.5 Amps but the peak pulse current can safely reach 75 Amps.
Our exibit is new and was donated in its original wooden crate.
The main bulb of the envelope is 150 mm in diameter, and overall excluding the leads is 395 mm tall.