The AC/ME is an example of an early tuning indicator. It would be mounted horizontally so that the domed end window was visible through the front panel of the radio. In use the radio would be tuned and when the green display had spread to its maximum the correct tuning had be achieved.

The round screen has a centre electrode. When on a small V of bright green would be seen. In terms of a clock face the V would be from 11 to 1. With a maximum signal the bright green display would extend from 7 to 5.

The classic envelope is 36 mm in diameter and, excluding the B7 base pins, is 86 mm tall.

 
Pin Connections

B7	1	2	3	4	5	6	7
	-	g	t	h	h	k	a

 
Absolute Maximum Operating Conditions

CRT	Vh	Ah	Va	mAa	Vg
	4.0	0.5	250	1.5	-22

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 08 June 2007 {find valves by name}