tube , ***
vacuum tube
thermionic vacuum tube
thermionic tube
electron tube
thermionic valve

The EL34 is a thermionic valve or vacuum tube of the power pentode type.

It used thermionic valves (vacuum tubes) to implement the logic.

This machine used thermionic valves to generate a clock frequency of 125 kHz.

They used thermionic valves (vacuum tubes) and binary representation of numbers.

A nonode is a type of thermionic valve that has nine active electrodes.

The EL84 is a thermionic valve of the power pentode type.

After the war new products needed to be found and the company started to manufacture radio parts such as thermionic valves and eventually a radio.

Additionally, the machine used 4,200 thermionic valves that had to be replaced constantly.

Radio as we know it depended on the development of the vacuum tube (thermionic valve) (ca. 1906-08) which allowed amplification.

The design had one to two thousand thermionic valves (vacuum tubes).