The DG210 from Tungsram is a bi-grid mixer for use up to 1 MHz. It was described as a combined oscillator and mixer and thus made a saving of one valve. The mixer is an essential component of the superhet receiver. The original early 1920s bi-grid was a space charge valve designed to operate at very low HT voltages.
The dome carries the Tungsram name, identifies it as a Barium Tube (Azide process), gives the Type designation, filament voltage and then a figure of 20 Volts. The data sheet gives 20 Volts as the second grid voltage.
The balloon envelope is 47 mm in diameter, and excluding the B4 base pins is 88 mm tall.
Reference: 4064. Type DG210 was first introduced in 1931.
Absolute Maximum Operating Conditions¶
Updated June 30, 2017. shape:thin.glass.tube construction:all.glass type:bi-grid age:1920.1930 base:b4 heater:2.0v pins:4 pin:1.a pin:2.g2 pin:3.f pin:4.f pin:sc.g1