Solid state thyratron

Claim 2

A solid state replacement device for a thyratron, comprising: a. a base having a plurality of pins corresponding to the pins of the thyratron, to enable said replacement to be plugged into a corresponding thyratron socket, b. a gate controlled thyristor circuit having an anode and a cathode connected to the pins normally used for connection with the anode and cathode of the thyratron, c. a DC power supply with input connected to the pins normally used by the filament of the thyratron, and d. a voltage sensitive device connected between said power supply and at least one gate electrode of said gate controlled thyristor circuit, said voltage sensitive device having a gate electrode connected to the pin normally used by the grid of the thyratron to enable control voltages applied to the grid pin to control said voltage sensitive device to operate said thyristor circuit to provide response characteristics on the pins of said base substantially the same as those provided by a corresponding thyratron.

Claim 3

The device of claim 1 wherein said voltage sensitive device is a field effect transistor (FET) having: a. a source electrode connected to at least one gate electrode of said thyristor circuit, b. a drain electrode connected to the positive voltage output of said power supply, and c. a gate electrode connected to the pin normally used by the grid of the thyratron.

Claim 4

The device of claim 2 further comprising a diode and a current limiting resistor connected in series between said gate electrode of said FET and its corresponding pin.

Claim 5

The device of claim 3 further including a diode connected between the pin normally used by the screen grid of the thyratron and the gate of said FET to enable said replacement device to provide the equivalent of screen grid control in response to corresponding voltages applied thereto, and to cooperate with said FET gate diode to provide isolation between the grid and screen grid pins.

Claim 6

The device of claim 3 wherein the firing voltage of said FET is determined by the value of said resistor in series with the gate electrode of said FET and by the voltage output of said power supply.

Claim 7

The device of claim 2 further comprising a resistance circuit in series with said FET between said voltage output of said power supply and said thyristor circuit to limit the FET current.

Claim 8

The device of claim 6 wherein said resistance network further includes a zener diode connected between said FET and said thyristor circuit to provide bias for said FET.

Claim 9

The device of claim 1 further comprising a diode and a zener diode connected between the pins corresponding to the grid and cathode elements of the thyratron to provide a low impedance path for positive signals applied to the ''''grid'''' pin, similar to thyratron grid conduction.

Claim 10

The device of claim 1 wherein said power supply is a full wave bridge rectifier.

Claim 11

The device of claim 1 wherein said power supply is a full wave voltage doubler.

Claim 12

The device of claim 1 further comprising a resistor connected between the ''''grid'''' pin and the ''''cathode'''' pin of said base to provide the equivalent of thyratron grid input impedance.

Claim 13

The device of claim 1 further comprising a diode connected between the ''''anode'''' pin and the anode of a thyristor in said thyristor circuit to prevent transistor action in said thyristor.

Claim 14

The device of claim 1 wherein said thyristor circuit further comprises: a. two control tHyristors connected in series, b. voltage divider resistors connected in series with said control thyristors between said control thyristors and the ''''anode'''' pin and between said control thyristors and the ''''cathode'''' pin to limit the control thyristor current and to cooperate with said control thyristors to form a voltage divider network, c. separate series diode and resistor networks each connected in series between the gate electrode of a corresponding said control thyristor and said voltage sensitive device, to limit the current through said voltage sensitive device and to balance the control thyristor gate impedances, and d. a main SCR having the anode and cathode thereof connected to the pins normally used for connection with the anode and cathode of the thyratron, and having the gate thereof connected to said control thyristor voltage divider network.

Claim 15

A solid state replacement device for a thyratron, comprising: a. a base having a plurality of pins corresponding to the pins of the thyratron, to enable said replacement to be plugged into a corresponding thyratron socket, b. a gate controlled thyristor circuit having an anode and a cathode connected to the pins normally used for connection with the anode and cathode of the thyratron, c. a diode connected between the ''''anode'''' pin and the anode of a thyristor in said thyristor circuit to prevent transistor action in said thyristor, d. a DC power supply with input connected to the pins normally used by the filament of the thyratron, e. a field effect transistor (FET) connected between said power supply and at least one gate electrode of said gate controlled thyristor circuit, said FET having a gate electrode connected to the pin normally used by the grid of the thyratron, a source electrode connected to at least one gate electrode of said thyristor circuit, and a drain electrode connected to the positive voltage output of said power supply, f. a diode and a current limiting resistor connected in series between said gate electrode of said FET and its corresponding pin, g. a resistance circuit in series with said FET between said voltage output of said power supply and said thyristor circuit to limit the FET current, and h. a resistor connected between the ''''grid'''' pin and the ''''cathode'''' pin of said base to provide the equivalent of thyratron grid input impedance, said solid state replacement device enabling control voltages applied to the ''''grid'''' pin to control said FET to operate said thyristor circuit to provide response characteristics on the pins of said base substantially the same as those provided by a corresponding thyratron.

Claim 16

A solid state replacement device for a thyratron, comprising: a. a base having a plurality of pins corresponding to the pins of the thyratron, to enable said replacement to be plugged into a corresponding thyratron socket, b. a gate controlled thyristor circuit having an anode and a cathode connected to the pins normally used for connection with the anode and cathode of the thyratron, c. a diode connected between the ''''anode'''' pin and the anode of a thyristor in said thyristor circuit to prevent transistor action in said thyristor, d. a DC power supply with input connected to the pins normally used by the filament of the thyratron, e. a field effect transistor (FET) connected between said power supply and at least one gate electrode of said gate controlled thyristor circuit, said FET having a gate electrode connected to the pin normally used by the grid of the thyratron, a source electrode connected to at least one gate electrode of said thyristor circuit, and a drain electrode connected to the positive voltage output of said power supply, f. a diode and a current limiting resistor connected in series between said gate electrode of said FET and its corresponding pin, g. a resistance circuit in series with said FET between said voltage output of said power supply and said thyristor circuit to limit the FET current, and h. a resistor connected between the ''''grid'''' pin and the ''''cathode'''' pin of said base to provide the equivalent of thyratron grid input impedance, said solid state replacement device enabling control voltages applied to the ''''grid'''' pin to control said FET to operate said thyristor circuit to provide response characteristics on the pins of said base substantially the same as those provided by a corresponding thyratron.