Abstract: An improved drive circuit is provided for a DC motor. The drive circuit includes: a DC power source; a relay having a normally open contact and a normally closed contact; a DC motor electrically connected through the normally open contact of the relay to the power source; and a discharge circuit connected in parallel to the DC motor. More specifically, the discharge circuit is coupled to the normally closed contact of the relay and operable to inhibit current flow from the DC motor until the relay has settled in a closed position.

Abstract: An improved drive circuit is provided for a DC motor. The drive circuit includes: a DC power source; a relay having a normally open contact and a normally closed contact; a DC motor electrically connected through the normally open contact of the relay to the power source; and a discharge circuit connected in parallel to the DC motor. More specifically, the discharge circuit is coupled to the normally closed contact of the relay and operable to inhibit current flow from the DC motor until the relay has settled in a closed position.

Abstract: A control circuit that activates and deactivates a motor start winding at different motor rpm trip points provides improved accuracy in the trip points by automatically compensating for changes in motor current caused by variations in line voltage and motor winding temperature.

Abstract: A control circuit for an electric motor having start, low speed and high speed windings reactivates the start winding at different reduced motor speeds depending upon whether the motor is running on the low speed winding or the high speed winding. Reactivation of the start winding while the motor is running on the low speed winding automatically deactivates the low speed winding and activates the high speed winding.

Abstract: A control circuit for a two speed electric motor includes high and low speed electronic switches. The high speed electronic switch is biased off when the low speed electronic switch is biased on. The low speed run winding of the motor is activatable only through the low speed electronic switch. The high speed run winding of the motor is activatable either directly through a high speed setting of a speed selector switch or through the high speed electronic switch in a low speed setting of the speed selector switch. Upon activation of the motor start winding, the low speed electronic switch is off and the high speed electronic switch is on.

Abstract: An electronic chime for generating an aural tone comprising an oscillator, an input signal generator for the oscillator, the input signal generated thereby decaying from an initial value to a lower value. The oscillator includes a signal processor (i.e., an amplifier) with a feedback frequency generator connected to the input of the amplifier and being responsive to the output of the amplifier for impressing a desired frequency on the input signal to the amplifier. A speaker and a driver for the speaker are provided, the latter being responsive to the output of the oscillator so as to sound a chime-like aural signal whose amplitude (volume) decays at a predetermined rate while the frequency of the signal remains substantially constant.

Abstract: A security alarm transmission system for protecting a building includes a plurality of alarm transmitter units each having a transmitter circuit controlled by associated condition sensors to generate coded alarm signals which are inductively coupled to a pick-up loop extending around the periphery of the building and extended to a receiver connected to the loop which decodes the alarm signals and provides a suitable alarm indication. The alarm transmitter unit is adaptable to provide different alarm outputs for indicating fire in the building or an unauthorized entry of the building, or an emergency condition, for example. The multipurpose alarm transmitter unit comprises a housing unit for containing the transmitter circuit, the housing permitting the transmitter circuit to be controlled by normally open or normally closed switches, and a mounting assembly which permits convenient installation of the transmitter unit at desired locations.