Transistorized flasher circuit

Claim 2

A flasher circuit comprising: a source of unidirectional electric potential; a junction transistor having emitter, collector and base electrodes; a relay having an operating coil and normally disengaged contacts which are movable into engagement in response to energization of said coil, said operating coil being serially connected with said source and the emitter and collector electrodes of said junction transistor, said contacts being connected to said source and a series circuit comprising a manually operable switch and a lamp load; a diode connected to the junction of said contacts and said series circuit; and circuit means connected to said source and including: a capacitor charging circuit connected to said relay contacts and including a first resistor and a capacitor connected in series with said diode to provide a charging path for capacitor charging current when said contacts are disengaged, a discharging circuit including a second resistor connected in parallel with said first resistor and said capacitor to provide a discharging path for capacitor discharging current when said contacts are engaged, a programmable unijunction transistor including anode, gate, and cathode electrodes, said anode electrode being connected to the junction of said first resistor and said capacitor, a voltage divider connected to said source, and a third resistor connected to said source, said gate electrode being connected to said voltage divider, said cathode electrode being connected to said third resistor and to the base electrode of said junction transistor.

Claim 3

A flasher circuit, adapted to be connected to a source of unidirectional electric potential, for intermittently energizing a signal lamp, comprising: a relay including an electrically energizable operating coil, and a pair of contacts adapted to be connected to said source and movable between disengaged and engaged positions in response to energization and deenergization of said operating coil; a lamp load; switch means connected in circuit with said pair of contacts and said lamp load and being movable between a closed position and an open position for respectively connecting and disconnecting said lamp load to and from said source through said pair of contacts in the engaged position; a transistor having base, emitter and collector electrodes, said emitter and collector electrodes being connected in series with said operating coil for establishing current flow from said source to said operating coil when said transistor is conductive so that said pair of contacts is moved to said engaged positions to energize the lamp load; and circuit means connected in circuit with said transistor and said switch means and operable upon application of said electric potential thereto, when said switch means moves to said closed position, to cyclically and intermittently trigger said transistor between conductive and non-conductive states and cyclically establish current flow from said source through said emitter and collector electrodes and said operating coil so that said pair of contacts move between said disengaged and said engaged positions and energize the lamp load; said circuit means comprising a series charging circuit, connected in parallel circuit with said pair of contacts, including a first resistor, a chargeable and dischargeable capacitor, and a diode connected to said switch means permitting the flow of current in a first direction to said switch means and said load when said contacts are in said disengaged positions and for blocking a reverse flow of current isolating said first resistor and capacitor from said lamp load when said contacts are in said engaged positions; a discharging circuit including a second resistor connected in parallel with said first resistor and said capacitor providing a discharge path for said capacitor when said contacts are in said engaged positions; and a programmable unijunction transistor having anode, gate, and cathode electrodes, said anode electrode being connected to the junction of said capacitor and said first resistor, said gate electrode being adapted to be connected in circuit with said source, said cathode electrode being connected to said base electrode.

Claim 4

A flasher circuit, adapted to be connected to a source of unidirectional electric potential, for intermittently energizing a signal lamp, comprising: a relay including an electrically energizable operating coil, and a pair of contacts adapted to be connected to said source and movable between disengaged and engaged positions in response to energization and deenergization of said operating coil; a lamp load; switch means connected in circuit with said pair of contacts and said lamp load and being movable between a closed position and an open position for respectively connecting and disconnecting said lamp load to and from said source through said pair of contacts in the engaged position; a transistor having base, emitter and collector electrodes, said emitter and collector electrodes being connected in series with said operating coil for establishing current flow from said source to said operating coil when said transistor is conductive so that said pair of contacts is moved to said engaged positions to energize the lamp load; and circuit means connected in circuit with said transistor and said switch means and operable upon application of said electric potential thereto, when said switch means moves to said closed position, to cyclically and intermittently trigger said transistor between conductive and non-conductive states and cyclically establish current flow from said source through said emitter and collector electrodes and said operating coil so that said pair of contacts move between said disengaged and said engaged positions and energize the lamp load; said circuit means comprising a series charging circuit, connected in parallel circuit with said pair of contacts, including a first resistor, a chargeable and dischargeable capacitor, and a diode connected to said switch means permitting the flow of current in a first direction to said switch means and said load when said contacts are in said disengaged positions and for blocking a reverse flow of current isolating said first resistor and capacitor from said lamp load when said contacts are in said engaged positions; a discharging circuit including a second resistor connected in parallel with said first resistor and said capacitor providing a discharge path for said capacitor when said contacts are in said engaged positions; and a programmable unijunction transistor having anode, gate, and cathode electrodes, said anode electrode being connected to the junction of said capacitor and said first resistor, said gate electrode being adapted to be connected in circuit with said source, said cathode electrode being connected to said base electrode.