The Philips 4152 thermal delay switch has significant switching electrodes at the top of the envelope. Such delay switches were designed to give a rectifier, such as a Mercury vapour type, time to reach working temperature before anode volts were applied. Premature application of anode Volts would lead to the early failure of the rectifier.

The wide glass tube envelope is 30 mm in diameter and, excluding the IO base pins, is 120 mm tall.

 
Absolute Maximum Operating Conditions

Delay	Ah	Va	mAa
	0.092	220	1,500

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 01 February 2008 {find valves by name}