Flasher circuit with means for adjusting flash rate and duration

Claim 2

In an electronic flasher circuit: a pair of terminal for connection to a power source; a first, second and third transistor; a series circuit connected across the terminals including a lamp load and the collector-emitter path of the third transistor; the second transistor having its emitter-collector path connected between one of the terminals and the base of the third transistor; the first transistor having its collector connected to the base of the second transistor; means connected across the terminals for applying a biasing voltage to the emitter of the fist transistor; a capacitor connected between the base of the first transistor and one of the terminals; and a charging circuit for the capacitor connected between the base of the first transistor and the junction of the lamp load and third transistor collector in said series circuit.

Claim 3

A circuit as defined in claim 1 wherein said charging circuit includes variable resistance means for controlling the charging rate of the capacitor.

Claim 4

A circuit as defined in claim 1 wherein said means for applying a biasing voltage includes variable resistance means for adjusting the level of the biasing voltage.

Claim 5

A circuit as defined in claim 1 together with switching means in said capacitor charging circuit for rendering it inoperable.

Claim 6

A circuit as defined in claim 1 wherein the charging of the capacitor alerts the voltage at the base of the first transistor with respect to its emitter voltage so that the transistor switches from a nonconducting to a conducting state, the switching of the transistor to a conducting state being operable to cause the second and third transistors in turn to conduct whereby the lamp load is energized; and means in the circuit connected between the emitter of the first transistor and the junction of the lamp load and third transistor collector that operates when the third transistor is conducting to alter the emitter voltage of the first transistor so that full conduction of the latter is insured.

Claim 7

In an electronic flasher circuit: a pair of terminals for connection to a power source; a transistor; means in the circuit, when power is applied to the terminals, to apply a biasing potential to the emitter of the transistor; said last-named means including variable resistance means for adjusting the biasing potential to the desired level; a capacitor connected between the base of the transistor and one of the terminals; means in the circuit to charge the capacitor and thereby alter the potential at the base of the transistor so that it starts to conduct; said last-named means including variable resistance means for controlling the capacitor charging rate; a series circuit connected across the terminals including a lamp load and the collector-emitter path of another transistor; and means in the circuit connected between the collector of the first-named transistor and base of the last-named transistor to cause the latter to conduct when the former is conducting whereby substantially full power is applied across the lamp load causing it to be energized.

Claim 8

In an electronic flasher circuit: a pair of terminals for connection to a power source; a transistor; means in the circuit, when power is applied to the terminals, to apply a biasing potential to the emitter of the transistor; said last-named means including variable resistance means for adjusting the biasing potential to the desired level; a capacitor connected between the base of the transistor and one of the terminals; means in the circuit to charge the capacitor and thereby alter the potential at the base of the transistor so that it starts to conduct; said last-named means including variable resistance means for controlling the capacitor charging rate; a series circuit connected across the terminals including a lamp load and the collector-emitter path of another transistor; and means in the circuit connected between the collector of the first-named transistor and base of the last-named transistor to cause the latter to conduct when the former is conducting whereby substantially full power is applied across the lamp load causing it to be energized.

Claim 9

A circuit as defined in claim 6 together with means connected between the emitter of the first-named transistor and junction of the lamp load and collector of the last-named transistoR that operates when the latter is conducting to alter the potential at said emitter whereby full conduction of the first-named transistor is insured.

Claim 10

A circuit as defined in claim 6 wherein said capacitor charging means includes a switching device for rendering the charging means inoperable.

Claim 11

In an electronic flasher circuit: a pair of terminals for connection to a power source; a first, second and third transistor; a series circuit connected across the terminals including a lamp and the collector-emitter path of the third transistor; the second transistor having its emitter-collector path connected between one of the terminals and the base of the third transistor; the first transistor having its collector-emitter path connected between the base of the second transistor and the other of said terminals; means in the circuit for applying a biasing potential to the emitter of the first transistor; a capacitor connected between the base of the first transistor and one of the terminals; a charging circuit for the capacitor, including series connected resistors, connected between the base of the first transistor and junction of the lamp and third transistor collector in said series circuit; said capacitor being charged through the lamp and charging circuit, when power it applied across the terminals, to alter the base potential of the first transistor with respect to its emitter potential and cause it to switch from a nonconducting to a conducting state; conduction of the first transistor causing base current to flow in the second transistor whereby it conducts and causes the third transistor to conduct and the lamp to be energized; and resistance means connected between the emitter of the first transistor and collector of the third transistor operable to alter the biasing potential at the emitter when the third transistor is conducting, the altering of the emitter potential of the first transistor in conduction with the altering of its base potential serving to insure full conduction of the transistor.

Claim 12

In an electronic flasher circuit: a pair of terminals for connection to a power source; a first, second and third transistor; a series circuit connected across the terminals including a lamp and the collector-emitter path of the third transistor; the second transistor having its emitter-collector path connected between one of the terminals and the base of the third transistor; the first transistor having its collector-emitter path connected between the base of the second transistor and the other of said terminals; means in the circuit for applying a biasing potential to the emitter of the first transistor; a capacitor connected between the base of the first transistor and one of the terminals; a charging circuit for the capacitor, including series connected resistors, connected between the base of the first transistor and junction of the lamp and third transistor collector in said series circuit; said capacitor being charged through the lamp and charging circuit, when power it applied across the terminals, to alter the base potential of the first transistor with respect to its emitter potential and cause it to switch from a nonconducting to a conducting state; conduction of the first transistor causing base current to flow in the second transistor whereby it conducts and causes the third transistor to conduct and the lamp to be energized; and resistance means connected between the emitter of the first transistor and collector of the third transistor operable to alter the biasing potential at the emitter when the third transistor is conducting, the altering of the emitter potential of the first transistor in conduction with the altering of its base potential serving to insure full conduction of the transistor.

Claim 13

A circuit as defined in claim 9 wherein one of the resistors in the charging circuit is variable to enable the charging rate of the capacitor to be adjusted.

Claim 14

A circuit as defined in claim 9 wherein said means for applying a biasing potential to the emitter of the first transistor includes variable resistance means for adjusting the initial level of the biasing voltage. 12. In an electronic flasher circuit: a pair of terminals for connection to a power source; a first, second and third transistor; a series circuit connected across the terminals including a lamp and the collector-emitter path of the third transistor; the second transistor having its emitter-collector path connected between one of the terminals and the base of the third transistor; the first transistor having its collector connected to the base of the second transistor; a voltage divider connected across the terminals and having a plurality of resistors one of which is variable; the emitter of the first transistor being connected to an intermediate point on the voltage divider; a capacitor connected between the base of the first transistor and one of the terminals; a charging circuit for the capacitor connected between the base of the first transistor and junction of the lamp and third transistor collector, said charging circuit including a plurality of series connected resistors one of which is variable; said capacitor being charged through the lamp and charging circuit, when power is applied across the terminals, to alter the base potential of the first transistor with respect to its emitter potential and cause it to switch from a nonconducting to a conducting state; conduction of the first transistor causing base current to flow in the second transistor whereby it conducts and causes the third transistor to conduct and the lamp to be energized; and resistance means connected between said voltage divider intermediate point and the collector of the third transistor to provide a circuit In parallel with a portion of the voltage divider when the third transistor is conducting.

Claim 15

A circuit as defined in claim 12, wherein one of the resistors in the capacitor charging circuit is arranged in the circuit in parallel with a diode that is operable to short out the resistor when the capacitor discharges.

Claim 16

A circuit as defined in claim 12, together with a second pair of terminals arranged in the circuit so that an optional photocell connected across the terminals will be in parallel with the capacitor, the photocell being adapted in the presence of sufficient natural light to reduce the voltage across the capacitor to a value at which the circuit will cease to operate.

Claim 17

A circuit as defined in claim 14 together with means in the capacitor charging circuit and cooperable with the photocell that can be actuated to cause the lamp to burn continuously when the resistance of the photocell increases due to insufficient natural light.

Claim 18

A circuit as defined in claim 15 wherein said last-named means is a double pole-double throw switch.