| 摘要 |
<p>-16- RCA 75,379 SHUTTER CONTROL SYSTEM A skylight shutter is driven by a battery-powered d.c. motor through transistor switches which in turn are operated by Schmitt triggers. A voltage dividing network derives control signals for the triggers 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 network provides overriding signals for controlling operation of the Schmitt triggers independently of the control otherwise furnished by the photosensor and variable resistors in order to place the shutter in a closed position and reduce radiation loss through the shutter during evening hours.</p> |
