Light controlled automatic curtain circuit

The working principle of the circuit is analyzed as follows: every morning, light shines on the silicon photovoltaic cell, generating an electromotive force. This electromotive force will
turn on the transistor VT1 and charge the capacitor cl. As the capacitor C. The upper voltage continues to rise, and the emitter current of VT2 also gradually increases. When this current
reaches the thyristor gate trigger current , the thyristor is triggered to conduct, the relay K is closed, the contacts are switched, and the DC motor is energized
and rotates , and after deceleration The driver drives the curtain to slowly move to a stop.