This invention relates to control circuits and, more particularly, to a circuit for energizing a load device, such as the ringer of a telephone set, with low-frequency, high-amplitude pulses.Īn object of this invention is to provide a new and improved circuit of small and compact size for providing low-frequency relatively high-amplitude pulses for energizing a load device, such as a ringer of a telephone set.Īnother object is to provide a circuit of the type described having a high-frequency oscillator and a capacitor charging circuit for providing a positive-going pulse during each period of operation of the high-frequency oscillator, a pulse circuit for providing a negative-going pulse each time it is rendered operative, and a low-frequency oscillator for rendering said high-frequency oscillator and the pulse circuit alternately operative. The circuit of claim 8, wherein said multivibrator includes first and second alternately conductive transistors, means operatively associated with said first multivibrator transistor and said oscillator for rendering said oscillator operative when said first multivibrator transistor is conductive and means operatively associated with said second multivibrator transistor and said pulse circuit first transistor for rendering said pulse circuit conductive when said second multivibrator transistor is conductive.
#Bipolar square wave wavetek series#
The circuit of claim 1, wherein said pulse circuit includes a first transistor having an emitter collector circuit connected across said input circuit in series with said output circuit and means operatively associated with said multivibrator and said first transistor for renderingĩ.
The circuit of claim 6, and a ringer winding of a telephone setĨ. The circuit of claim 5, wherein said transformer includes an output winding and wherein said diode network comprises a first pair of reversely connected diodes connected across said output winding and a second pair of reversely connected diodes connected across said output winding, a capacitor connected between the common connections of said pairs of diodes, and means connecting said capacitor in series with said outputħ. The circuit of claim 4, wherein said oscillator comprises a transformer having a pair of primary windings a pair of transistors having emitter-collector circuits connected reversely in series across said primary windings means connecting said primary windings and said emitters of said transistors to opposite sides of said input circuit a capacitor connected across said windings for determining the frequency of oscillation of said oscillator said transformer having a secondary feedback winding and means operatively associated with said multivibrator and the bases of said oscillator transistors for periodically renderingĦ.
The circuit of claim 3, wherein said pulse circuit includes a first transistor having an emitter circuit connected across said input circuit in series with said output circuit and means operatively associated with said multivibrator and said first transistor for rendering said transistorĥ.
The circuit of claim 2, wherein said second means comprises aĤ. The circuit of claim 1, wherein said first means comprises a diode rectifier network energized by said oscillator and a capacitor chargableģ. A circuit for energizing an output circuit with low-frequency pulses, said circuit including: an input circuit of direct current an oscillator for providing high-frequency alternating current connected across said input circuit first means operatively associated with said oscillator and said output circuit and energized by said high-frequency alternating current for providing a positive-going pulse across said output circuit each time said oscillator is rendered operable a pulse circuit connected across said input circuit and operatively associated with said output circuit for providing negative-going pulses across said input circuit and second means connected across said input circuit and operatively associated with said oscillator and said pulse circuit for rendering said oscillator and said pulse circuit alternately operative at a frequencyĢ.
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