Impedance switching timer

Claim 2

In a timing circuit of the character described, the combination with a source of alternating current, of a diode bridge circuit for full-wave rectification having its terminals connected across the current source, a charging circuit consisting of a high ohmic value resistor in series relation with a first condenser, the resistor being connected to the positive terminal of the bridge and the condenser being connected to the negative terminal of the bridge. A parallel conducting circuit consisting of a magnetically actuated reed switch in series connected relation with an inductance coil, the reed switch being connected to said positive terminal and the coil being connected to the negative terminal of the bridge circuit, said coil having inductive relation with the reed switch whereby the reed switch is caused to close when current flows through the coil, a trip circuit including a trigger diode which is caused to close when a preselected voltage is applied to its terminals, a conductor connecting the trigger diode to the charging circuit between the resistor and the first condenser and to the conducting circuit between the reed switch and the inductance coil, whereby when the first condenser is charged to the preselected voltage the diode closes to discharge the first condenser through the inductance coil, a second condenser connected across the inductance coil for smoothing out the current flow as rectified by the bridge and a diode having one side thereof electrically connected to said conductor at a location between the trigger diode and its connection to the charging circuit and having its other side connected to the positive terminal of the bridge circuit, whereby the first condenser may fully discharge before another charging of said condenser begins to take place.

Claim 3

In a timing circuit having terminals connected across a source of electric current, in combination, a first resistor and a first condenser, said first resistor having electrical connection to one terminal and having a series connected relation with the first condenser which is connected to the other terminal, said resistor having a relatively high resistance value so as to cause the condenser to charge at a relatively slow preselected rate, first switch means of the sensitive-to-voltage type and having such connection with the first resistor-first condenser series circuit that the first condenser upon discharge will cause current to flow through the said first switch means, an inductance coil and second switch means in series connected relation, the inductance coil having electrical connection to one terminal and the second switch means being connected to the other terminal of the timing circuit, said second switch means being glass enclosed and of the magnetically actuated type and the inductance coil having an inductive relation therewith, said coil and second switch means having such electrical connection with the first switch means of the sensitive-to-voltage type that upon current flow taking place through the same the said current is caused to also flow through the inductance coil, whereby the second switch means is caused to close due to the magnetic action of the inductance coil on the second switch means when current flows through the inductance coil, said second switch means when closed together with the inductance coil providing a path for current flow of considerably less impedance than the path provided by the first resistor of high ohmic value and its series connected first condenser, a second condenser connected across the inductance coil for maintaining current flow through the coil for as long as the second switch means remains closed, and a diode having one side thereof electrically connected in circuit between said first switch means of the sensitive-to-voltage type and the connection thereof to the first resistor-first condenser series circuit and having its other sIde connected to the positive terminal of the timing circuit, whereby the first condenser may fully discharge before another charging of said condenser starts to take place.

Claim 4

In a timing circuit having terminals connected across a source of electric current, in combination, a first resistor and a first condenser, said first resistor having electrical connection to one terminal and having a series connected relation with the first condenser which is connected to the other terminal, said resistor having a relatively high resistance value so as to cause the condenser to charge at a relatively slow preselected rate, first switch means of the sensitive-to-voltage type and having such connection with the first resistor-first condenser series circuit that the first condenser upon discharge will cause current to flow through the said first switch means, an inductance coil and second switch means in series connected relation, the inductance coil having electrical connection to one terminal and the second switch means being connected to the other terminal of the timing circuit, said second switch means being glass enclosed and of the magnetically actuated type and the inductance coil having an inductive relation therewith, said coil and second switch means having such electrical connection with the first switch means of the sensitive-to-voltage type that upon current flow taking place through the same the said current is caused to also flow through the inductance coil, whereby the second switch means is caused to close due to the magnetic action of the inductance coil on the second switch means when current flows through the inductance coil, said second switch means when closed together with the inductance coil providing a path for current flow of considerably less impedance than the path provided by the first resistor of high ohmic value and its series connected first condenser, a second condenser connected across the inductance coil for maintaining current flow through the coil for as long as the second switch means remains closed, and a diode having one side thereof electrically connected in circuit between said first switch means of the sensitive-to-voltage type and the connection thereof to the first resistor-first condenser series circuit and having its other sIde connected to the positive terminal of the timing circuit, whereby the first condenser may fully discharge before another charging of said condenser starts to take place.

Claim 5

A timing circuit having terminals connected across a source of electric current as defined by claim 2, wherein the first switch means of the sensitive-to-voltage type consists of a diac which provides a normally open switch, wherein its connection in the timing circuit is such that the diac is caused to close when the first condenser has been charged to a preselected value, and wherein with the closing of the diac the first condenser discharges through the same.