Fet control system employing a storage capacitor and switching tube means

Claim 2

The combination comprising: a field effect transistor having a source electrode, a drain electrode and a gate electrode, said source and drain electrodes interconnected with circuit means to form an electrical circuit operable to control functions in an electrical apparatus by changes in the conductivity of the source-drain electrode current path of said transistor: a capacitor connected to the gate electrode of said transistor; a source of control voltage; means for coupling said source of control voltage to said capacitor to establish the conductivity of said transistor, said means including a switching tube having a leakage resistance characteristic effective in preventing the leakage of stored charge from said capacitor and a switching characteristic requiring a voltage of a magnitude in excess of said control voltage to render said switching tube conductive; and means coupled to said switching tube and responsive to remotely generated signals for causing a voltage to be applied to said switching tube, said voltage being of a greater magnItude than said control voltage and sufficient to render said switching tube conductive.

Claim 3

The combination as defined in claim 1 wherein said switching tube is a neon gas tube.

Claim 4

The combination comprising: a field effect transistor having a source electrode, a drain electrode and a gate electrode, said source and drain electrodes interconnected with circuit means to form an electrical circuit operable to control functions in an electrical apparatus by changes in the conductivity of the source-drain electrode current path of said transistor; a capacitor connected to the gate electrode of said transistor; a source of positive control voltage and a source of negative control voltage; means for coupling said sources of control voltage to said capacitor to establish the conductivity of said transistor, said means including first and second switching tubes respectively coupling said sources of positive and negative control voltage to said capacitor, with each of said tubes exhibiting a leakage resistance characteristic effective in preventing the leakage of stored charge from said capacitor and a switching characteristic requiring a voltage of a magnitude in excess of said control voltages to render said switching tube conductive; and means coupled to said switching tube and responsive to remotely generated signals for selectively causing a voltage to be applied to one of said switching tubes, said voltage being of a greater magnitude than said control voltages and sufficient to render said selected one switching tube conductive.

Claim 5

The combination comprising: a field effect transistor having a source electrode, a drain electrode and a gate electrode, said source and drain electrodes interconnected with circuit means to form an electrical circuit operable to control functions in an electrical apparatus by changes in the conductivity of the source-drain electrode current path of said transistor; a capacitor connected to the gate electrode of said transistor; a source of positive control voltage and a source of negative control voltage; means for coupling said sources of control voltage to said capacitor to establish the conductivity of said transistor, said means including first and second switching tubes respectively coupling said sources of positive and negative control voltage to said capacitor, with each of said tubes exhibiting a leakage resistance characteristic effective in preventing the leakage of stored charge from said capacitor and a switching characteristic requiring a voltage of a magnitude in excess of said control voltages to render said switching tube conductive; and means coupled to said switching tube and responsive to remotely generated signals for selectively causing a voltage to be applied to one of said switching tubes, said voltage being of a greater magnitude than said control voltages and sufficient to render said selected one switching tube conductive.

Claim 6

The combination as defined in claim 3 wherein said first switching tube and said second switching tube are neon gas tubes.

Claim 7

The combination as defined in claim 3 wherein said field effect transistor is of the insulated gate variety.

Claim 8

The combination comprising: A semiconductor device having a first electrode, a second electrode and a control electrode exhibiting a high input impedance, said first and second electrodes interconnected with circuit means to form an electrical circuit operable to control functions in an electrical apparatus by changes in the conductivity of the first-second electrode current path of said semiconductor device; a capacitor connected to the control electrode of said device; a source of control voltage; means for coupling said source of control voltage to said capacitor to establish the conductivity of said semiconductor device, said means including a switching tube having a leakage resistance characteristic effective in preventing the leakage of stored charge from said capacitor and a switching characteristic requiring a voltage of a magnitude in excess of said control voltage to render said switching tube conductive; and means coupled to said switching tube and responsive to remotely generated signals for causing a voltage to be applied to said switching tube, said voltage being of a greater magnitude than said control voltage and sufficient to render said switching tube conductive.

Claim 9

The combination comprising: A semiconductor device having a first electrode, a second electrode and a control electrode exhibiting a high input impedance, said first and second electrodes interconnected with circuit means to form an electrical circuit operable to control functions in an electrical apparatus by changes in the conductivity of the first-second electrode current path of said semiconductor device; a capacitor connected to the control electrode of said device; a source of control voltage; means for coupling said source of control voltage to said capacitor to establish the conductivity of said semiconductor device, said means including a switching tube having a leakage resistance characteristic effective in preventing the leakage of stored charge from said capacitor and a switching characteristic requiring a voltage of a magnitude in excess of said control voltage to render said switching tube conductive; and means coupled to said switching tube and responsive to remotely generated signals for causing a voltage to be applied to said switching tube, said voltage being of a greater magnitude than said control voltage and sufficient to render said switching tube conductive.

Claim 10

An electric circuit comprising: a device having a first electrode, a second electrode and a control electrode with a high input impedance, the voltage at said control electrode determining the conductivity of the first to second electrode path of said device; a storage capacitor connected to the control electrode of said device; a transformer having a primary winding, a first secondary winding with a first end and a second end and a second secondary winding with a first end and a second end; a first switching tube connected to said control electrode; first means for interconnecting the first end of said first secondary winding and said first switching tube; a second switching tube connected to said control electrode; second means for interconnecting the first end of said second secondary winding and said second switching tube; a source of positive control voltage connected to the second end of said first secondary Winding; and a source of negative control voltage connected to the second end of said second secondary winding.

Claim 11

An electric circuit comprising: a device having a first electrode, a second electrode and a control electrode with a high input impedance, the voltage at said control electrode determining the conductivity of the first to second electrode path of said device; a storage capacitor connected to the control electrode of said device; a transformer having a primary winding, a first secondary winding with a first end and a second end and a second secondary winding with a first end and a second end; a first switching tube connected to said control electrode; first means for interconnecting the first end of said first secondary winding and said first switching tube; a second switching tube connected to said control electrode; second means for interconnecting the first end of said second secondary winding and said second switching tube; a source of positive control voltage connected to the second end of said first secondary Winding; and a source of negative control voltage connected to the second end of said second secondary winding.

Claim 12

An electric circuit as defined in claim 7 wherein said first means is a first inductor serially connected with a first capacitor, said first inductor and said first capacitor series resonant at a first frequency, and said second means is a second inductor serially connected with a second capacitor; said second inductor and said second capacitor series resonant at a second frequency.

Claim 13

An electric circuit as defined in claim 8 including means for remotely controlling the energization of the primary winding of said transformer at said first frequency and at said second frequency.

Claim 14

In signal processing apparatus of the type adapted to be remotely controlled by the transmission of remotely generated signals of predetermined frequencies, an electric circuit comprising: a field effect transistor having a source electrode, a drain electrode and a gate electrode, said source and drain electrodes interconnected with circuit means such that changes in the conductivity of the source-drain electrode current path of said transistor are operable to control functions in said apparatus; a storage capacitor connected to the gate electrode of said transistor; a first terminal adapted to be energized by a source of positive DC potential; a second terminal adapted to be energized by a source of negative DC potential; first means connecting said storage capacitor to said first terminal and including a first gaseous switching tube; second means for connecting said storage capacitor to said second terminal including a second gaseous switching tube; and means coupled to said first and said second gaseous switching tubes and responsive to said remotely generated signals for selectively causing an alternating voltage to be applied to one of said first and second gaseous switching tubes, said alternating voltage of a sufficient magnitude to ionize said selected one tube gas such that a low DC impedance path exists between one of said first and said second terminals and said storage capacitor.

Claim 15

In signal processing apparatus of the type adapted to be remotely controlled by the transmission of remotely generated signals of predetermined frequencies, an electric circuit comprising: a field effect transistor having a source electrode, a drain electrode and a gate electrode, said source and drain electrodes interconnected with circuit means such that changes in the conductivity of the source-drain electrode current path of said transistor are operable to control functions in said apparatus; a storage capacitor connected to the gate electrode of said transistor; a first terminal adapted to be energized by a source of positive DC potential; a second terminal adapted to be energized by a source of negative DC potential; first means connecting said storage capacitor to said first terminal and including a first gaseous switching tube; second means for connecting said storage capacitor to said second terminal including a second gaseous switching tube; and means coupled to said first and said second gaseous switching tubes and responsive to said remotely generated signals for selectively causing an alternating voltage to be applied to one of said first and second gaseous switching tubes, said alternating voltage of a sufficient magnitude to ionize said selected one tube gas such that a low DC impedance path exists between one of said first and said second terminals and said storage capacitor.