The TX8G performs the logical AND (conjunction) function: anode current flows only when control pulses are applied simultaneously to both control grids (Grid 2 and Grid 3). If a signal is present on only one grid, the discharge does not ignite. This makes the tube a physical implementation of a two-input AND gate in a single glass envelope.

A key design feature is the presence of a priming discharge on Grid 1, which creates initial ionization in the gas and significantly reduces the switching delay. Thanks to this, the tube achieves a response time of approximately 10⁻⁵ seconds, which was considered quite fast for its era.

The TX8G was developed in the early 1960s at the Moscow Electric Lamp Plant (MELZ) and was widely used in Soviet second-generation computers such as the Ural and Minsk series, as well as in industrial telecontrol and automation systems. Its simple and robust design ensures high reliability and a long service life.

Unlike semiconductor logic elements of later periods, the TX8G is immune to electromagnetic pulses and does not require a heated cathode, making it instantly ready for operation. These properties make it attractive today for restoring vintage computing equipment, creating retro demonstration stands, and teaching the principles of gas-discharge electronics.

⚠ IMPORTANT: Correct Pinout (bottom view, 6 pins)

• Pin 1: Anode (+)
• Pin 2: Grid 3 (Control Input B)
• Pin 3: Cathode (-)
• Pin 4: Not connected (NC / absent)
• Pin 5: Grid 1 (Priming / auxiliary discharge)
• Pin 6: Grid 2 (Control Input A)

Applications:

• Restoration of vintage Soviet computers (Ural, Minsk series)
• Retro electronics projects and logic demonstrators
• Educational physics and electronics demonstrations
• Replacement parts for industrial automation (relay logic circuits)