In addition to use as an audio amplifier in transformer-coupled circuits, the L210 was also suitable as an RF oscillator for superhet applications. This was before the advent of composite frequency changers.

Basically an improved DEL210, the MOV type L210 was one of the last MOV types to be made using the 'azide' process. Later samples of the L210 had conventional oxide-coated filaments which meant that they could be constructed in vertical format using mica spacers. This gave improvements in performance and life as well as a big reduction in microphony.

Manufactured from 1929, the electrode structure can be seen under the mirror deposit of the magnesium gettering at the top of the balloon. It lays horizontally with support struts at both sides of the open box like anode cavity.

The balloon envelope is 40 mm in diameter and, excluding the B4 base pins, is 78 mm tall.

 
Pin Connections

B4	1	2	3	4
	a	g1	f	f

 
Absolute Maximum Operating Conditions

Triode	Vh	Ah	Va	Vg	mAa	ra	gm	Pout
	2.0	0.1	150	-6	4.2	7,500	1.6	0.06W

This exhibit was last updated on 02 December 2007