Impressive Thyratron Circuit Schematic

A thyratron consists of a hot cathode an anode and one or more control grids between the anode and cathode in an airtight glass or ceramic envelope that is filled with gas.

Thyratron circuit schematic. First a 1 000 volt power supply was required to. 35 mw pulses oughta do it. But with a ceramic thyratron like the 7890 you don t see the purple glow.

It charges the caps rapidly up to nearly 100 volts the larger fraction is over the 2 2nf and a smaller one over the 68nf. Trigger circuit the trigger circuit uses several minor variations on a standard pulse generator. Grid circuit grid spike suppression circuit grid driver circuit.

Typical grid spike suppression circuits current limiting and or matching resistor figure 3. Thyratron tube is a controlled version of the neon lamp specially designed for providing current supply to a load. This paper will discuss the development and performance of the solid state drivers for these thyratrons.

Now the current sink tube slowly discharges the caps until the voltage across both is less than 50 volts where upon the thyratron can fire again. Most of the design effort was in component selection circuit board layout and transient immunity. The schematic is shown in fig.

These are voltage hold off commutation conduction and recovery see figure 2. The grid cathode voltage difference is now negative and the thyratron goes out of conduction. This circuit worked well but had several shortcomings.

The grid is held at about 50v and thus the thyratron fires. Note that the load s power source is ac which provides a clue about how the thyratron turns off after its been. Capacitors c29 and c30.