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Varian VA6152 Travelling Wave Tube

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This exhibit is an X band travelling wave tube donated by G3GRO. The Travelling Wave Tube acts as a high gain amplifier (40dB) at frequencies in the range 8-12 GHz. The output power is 15 Watts.
The connections are by flying leads. Green - cathode, White - heater cathode, Yellow - heater, Red - anode, Grey - collector, Brown - helix & base.
TWT amplifiers operate at lethal voltages, typically the helix needs a clean and very stable supply of 4000 - 5000 volts at up to 3 mA, the collector operates at 1450 volts at 15 mA, the anode at 2000 Volts at a few μA. The heater would be 6.3 V at about 0.7A. The RF signal is introduced at one coaxial socket and the output appears at the other.
The thin glass envelope is surrounded by magnets. The aluminium housing has a base plate 50 x 270 mm, the top radius is 19 mm.

This exhibit was last updated on August 19, 2014.