Abstract: A time responsive switching circuit for use with a single phase alternating current motor comprises a Triac in series with a start winding of the motor and controlled so as to disconnect the start winding after a predetermined time delay. The Triac is controlled by a timing circuit comprising a full wave rectifier bridge energized from the alternating current source, an RC charging network connected across the d.c. terminals of the bridge, a CMOS switching device responsive to the condition of the charging circuit, and an SCR controlled by the CMOS switching device. The SCR is switched off by the CMOS switching device after the chosen delay so as to remove the control potential from the Triac and so switch off the latter.

Abstract: An infrared intrusion detector has an optical system for gathering infrared radiation from discrete sensitive regions and focusing such received radiation onto an infrared radiation sensor. The detector includes a monitoring device to sound an alarm when radiation sensed reaches a predetermined level. The optical system comprises an optical collector for gathering radiation from a field which includes the sensitive regions and for converging such radiation onto a plurality of reflectors. Each reflector determines one of the discrete sensitive regions and, in turn, is oriented to reflect converging radiation gathered from a sensitive region on the detector. The invention provides a simple, efficient optic system for a broad field of gathering infrared radiation, concentrating and focusing it in a manner to provide sufficient levels of received radiation for purposes of detection.

Abstract: Improvements in battery operated smoke detector electronics including micro power astable multi-vibrator circuitry which has fast reliable switching of the inverters and electronic circuitry for single or dual ionization chamber smoke detector which maintains constant smoke detector sensitivity throughout the usable life of the battery.