Sensibly equivalent¶ to:
The EM1 is a magic eye tuning indicator. The control voltage swing required is 5 Volts to move from minimum to maximum shadow within the bowl of the screen.
The paint is peeling off identification is impaired. There is sufficient paint to confirm the Philips and the Miniwatt without too much difficulty. Under a glass the E and M can be determined but not the figure to distinguish between the one or the four. However, only the EM1 has the rod across the screen and this completes the identification.
The recessed end window. See EM1 for the Mullard branded version in almost pristine condition.
The wide glass tube envelope is 27 mm in diameter and, excluding the Ct8 base pins, is 73 mm tall.
References: Datasheet & 1043. Type EM1 was first introduced in 1937.
Absolute Maximum Operating Conditions¶
Updated December30, 2012.