Tone control signal circuit having tone pulses followed by continuous tone

Claim 2

A control signal circuit for controlling the current flow through an annunciator to cause intermittent operation followed by continuous operation of said annunciator comprising a timer circuit having a charging capacitor and resIstor connected in series and a transistor having its base connected between said charging capacitor and resistor, a multivibrator having its input connected to said timer circuit, an amplifier circuit having said annunciator as a load, said timer circuit, said multivibrator and said amplifier circuit being connected in parallel and across a power supply, the output of said multivibrator circuit being coupled to the input of said amplifier circuit so that said annunciator may be intermittently activated by the repetitive output frequency signal of said multivibrator, said timer circuit including a gating resistor as a load thereof which is connected to said multivibrator for biasing and to cease the operation of said multivibrator when said charging capacitor is charged to a predetermined potential value causing said annunciator to be continuously activated.

Claim 3

The control signal circuit of claim 1 characterized in that said amplifier circuit includes a transistor having its base connected across said power supply through biasing resistors.

Claim 4

The control signal circuit of claim 1 characterized by switch means connected in series with said power supply to place said circuit in operative condition.

Claim 5

A control signal circuit for operating a mechanical annunciator first by providing an intermittent signal to said annunciator for its operation followed by a continuous operation comprising a timer circuit, a multivibrator, and an amplifier circuit all connected in parallel and across a power supply, I. said amplifier circuit comprising an annunciator connected in series with an amplifier transistor, the base of which is connected across said power supply through biasing resistors II. said multivibrator comprising two transistors with companion RC networks and accompanying load resistors, the output of said multivibrator connected to the base of said amplifier transistor between said biasing resistors III. said timer circuit comprising a charging capacitor and charging resistor connected across said power supply with a timer transistor connected across said power supply in series with a gating resistor, said timer transistor and gating resistor also connected to the emitters of said multivibrator transistors, the base of said timer transistor connected between said charging capacitor and said charging resistor and IV. switch means connected in series with said power supply to place said circuit in operative condition causing a. said multivibrator to produce an intermittent signal on said annunciator to cause intermittent operation of the latter; and b. thereafter causing continuous operation of said annunciator when said charging capacitor has reached a predetermined potential causing conduction of said timer transistor and a voltage drop across said gating resistor sufficient to cease the oscillatory action of said multivibrator.

Claim 6

A control signal circuit for operating a mechanical annunciator first by providing an intermittent signal to said annunciator for its operation followed by a continuous operation comprising a timer circuit, a multivibrator, and an amplifier circuit all connected in parallel and across a power supply, I. said amplifier circuit comprising an annunciator connected in series with an amplifier transistor, the base of which is connected across said power supply through biasing resistors II. said multivibrator comprising two transistors with companion RC networks and accompanying load resistors, the output of said multivibrator connected to the base of said amplifier transistor between said biasing resistors III. said timer circuit comprising a charging capacitor and charging resistor connected across said power supply with a timer transistor connected across said power supply in series with a gating resistor, said timer transistor and gating resistor also connected to the emitters of said multivibrator transistors, the base of said timer transistor connected between said charging capacitor and said charging resistor and IV. switch means connected in series with said power supply to place said circuit in operative condition causing a. said multivibrator to produce an intermittent signal on said annunciator to cause intermittent operation of the latter; and b. thereafter causing continuous operation of said annunciator when said charging capacitor has reached a predetermined potential causing conduction of said timer transistor and a voltage drop across said gating resistor sufficient to cease the oscillatory action of said multivibrator.