Digitron

Such displays may be built using cathode ray tubes with electronically generated characters or by using arrays of digitrons and alphabet tubes, or by using electro-magnetic indicators.

In digit indicator lamps (digitrons), (one of which, type HH-1, is shown in the photograph in Fig. 1.15) the cathodes are made of nichrome wires shaped as the first ten digits and arranged one after the other along the lamp axis about one mm apart.

The time is displayed to 0.0001 second in digital form by means of digitrons (nixie tubes).

The LEDs display and keystroke identifying are accomplished by using HD7279A, which is an intelligent control chip for 8-bit LED digitrons and 64-key keyboard with serial interface.