Tacitron

a three-electrode hot-cathode hydrogen-filled tube. The tacitron is similar in design and use to a pulsed hydrogen thyratron, the only difference being in the structure of the control electrode, or grid. The grid of a tacitron has a very fine structure; the openings in the grid are not greater in size than the mean free path of the electrons in the gas. As a result, the instants at which the arc discharge is initiated and extinguished can be controlled without a reduction in the anode voltage.

Tacitrons are used in pulse-forming circuits operating at power levels of up to several hundred kilowatts to generate high-voltage (up to 25 kilovolts) electric pulses. For example, tacitrons are employed in radar pulse modulators and in power supplies for the pumping of pulsed lasers.

Like other hot-cathode gas-filled tubes, tacitrons have a low anode resistance and, accordingly, a high anode-voltage efficiency factor, which may reach 95–98 percent. Tacitrons are highly stable with respect to the instants at which the anode current is turned on or off, and the recovery time for the restoration of control properties is small. Consequently, tacitrons can be used for switching pulses with a duration of 10^–1–10^–2 microseconds at rates of up to several hundred kilohertz. Both glass and cermet envelopes are used in tacitrons.