This unit automatically buries glass doors when setting the vehicle in protection. Its principle is based on the load in excess of the specified current.
Fig.1
When setting the vehicle in protection, from the control circuit by the closing of the door locks of the relay coil 3 receives voltage, the relay is activated and the contacts K3.1 connects the capacitor C3 to voltage +12V through a resistor R5, the capacitor is charged.
After the control pulse charged capacitor is connected to the relay coil 2, it is activated and its contact To 2.2 energizes the timer, assembled on a chip DA1. At pin 7 of the chip is set to a voltage close to 0 and through resistor R3 to the base of transistor VT2 is served opening voltage. Through the opened transistor VT2 and the closed contacts turnips To 2.1 on the relay coil K2 is served restraint stress. Transistor VT1 thermostabilizers operating point of the transistor VT 2. The closed contacts of the relay K2.2 serves the voltage on the winding turnips K1. Through the resistor R4, the contacts P1 and turnips further, through the control button steklopodemnikam voltage is applied to the motor, the window is closed.
When the glass is fully closed, the engine decelerates, the current increases the voltage drop across the resistor R4, which leads to the closing of the transistor VT2. The winding of relay K2 is de-energized, its contacts open, de-energizing the entire circuit. Current protection is set resistor R2. The response time of the selected timer for 2-3 seconds more than the time required to fully close the glass. In normal mode it does not have time to work, it only works when, for any reason, will disappear load and will not be conditions for the closing of the transistor VT2.
Fig.2. Printed circuit Board
Publication: N. Bolshakov, rf.atnn.ru