Abstract: A system for controlling the operation of a load circuit coupled to an AC power distribution circuit includes an encoder which may be mounted in a wall switch box and coupled to a single conductor of the AC power distribution circuit for imposing thereon control signals by lengthening the zero crossings of the AC voltage. A decoder, also connected to the AC power distribution circuit at a remote location, detects the lengthened zero crossings and closes an electronic switch for energizing the load circuit. The encoder may be disconnected from the AC power distribution circuit, in which case the load circuit may be controlled by an external condition responsive device, such as a passive IR sensor. Visible light-responsive means may be provided for disabling the IR sensor during the day. The load circuit and the decoder can be turned off from the encoder location.

Abstract: A fire alarm system utilizes an ionization type aerosol detector having first and second intercommunicating and electrically in series ionization regions or chambers irradiated by a particle source. Electrodes are provided which operate in conjunction with a DC voltage source to establish a relatively large voltage gradient across the first region and a relatively small voltage gradient in the second region. Also, the location of the ion source and the effective volumes of the regions are arranged to establish a comparatively high ion density in the first region. In operation, the impedance or resistance of the first region to ion current flow is substantially uninfluenced by the presence of combustion or smoke aerosols due to the relatively high field gradient while the impedance or resistance of the second region is measurably changed thereby. The insensitivity of the first region to the presence of smoke is due to the high voltage gradient therein, as well as to the high ion density therein.

Abstract: Time pulse generator having biasing means therefor including a control device, which may be a transistor and means interconnecting the biasing means to the battery being monitored. The output of the time pulse generator is utilized to drive a signaling device to indicate a low level of battery energy and/or an alarm condition as detected by an external condition sensor.