Shutter control system

摘要

A skylight shutter is driven by a battery-powered d.c. motor through transistor switches operated by Schmitt triggers. A voltage dividing network derives the trigger signals by comparing the resistance of a photoresistor and a variable resistance, whose value determines the direction and degree the shutters are moved. A night sensor operates the Schmitt triggers independently of the remaining circuit for placing the shutters in a closed position to minimize radiation losses during evening hours.