The DG4-1 is badged as Mullard but was made by the parent company Philips in Holland. The tube was listed as current production in 1956 we think it dates from the late 1940s. The DG4-1 was designed for oscilloscope service and has a medium persistence green phosphor.

The DG4-1 has the same characteristics as the DB4-1 with a short persistence blue phosphor and the DP4-1 that had a blue phosphor with a long persistence.

The first anode voltage is given as 250 volts the second anode would have an average voltage of 800 Volts. At cut-off the grid would need to be at - 50 Volts. The sensitivity of the deflection plates is given as: x plates 130 mm per Volt and the y plates 210 mm per volt. This accords with standard practice of placing the y plates closer to the gun for a higher sensitivity.

The screen is 42 mm in diameter.

Excluding the B9G base pins the tube is 141 mm long.

 
Pin Connections

B9G	1	2	3	4	5	6	7	8	9
	h,k	y1	y2	a2	x1	x2	a1	g	h

 
Absolute Maximum Operating Conditions

CRT	Vh	Ah
	6.3	0.3

Thanks to Frank Philipse for supplying the above datasheet

This exhibit was last updated on 02 December 2007 {find valves by name}