GU-5B Russian TRIODE TUBE NOS. The GU-5B triode is used as a power amplifier tube at frequencies up to 110 MHz in RF equipment and RF heating generators. Date of manufacture 198x.. GENERAL Cathode: directly heated, carbonized thoriated tungsten. Height: at most 210 mm. Diameter: at most 100 mm. Mass: at most 2.5 kg. Robust […]