The DLS15 is a bi-metallic strip delay switch. The switch contacts operated and HT was applied to the protected circuit after the pre-set delay caused by the time the heater took to heat the bi-metallic strip to the point where the differential expansion of the metals caused it to bend sufficiently to contact the fixed post.

See DLS16 for the same switch but with a 6.3 Volt heater.

The wide glass tube envelope is 30 mm in diameter and, excluding the B4 base pins, is 55 mm tall.

 
Pin Connections

B4	1	2	3	4
	fc	mc	f	f

 
Absolute Maximum Operating Conditions

Delay	Vh	Ah	Va	mAa
	4.0	0.75	240	5,000

Thanks to Frank Philipse for supplying the above datasheet

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