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Electronic timer circuit with transistors

Using this circuit diagram can be designed a very simple electronic timer which can be used for timing wiper operation, lights of the vehicle and other electronic circuits.
As long as S1 is closed and the light lit. When contact S1 opens and the lamp is turned off, the entire battery voltage of 12 V is present on the switch. When the voltage on S1 starts to grow, assembly senses this. Transistor T3 and therefore, T1 and T2, resulting in open
increasing pressure on the S1 rises to 1V, after which growth slows more gradually resulting in decreased light intensity.
At a certain level of voltage on S1 transistor T4 opens, resulting blocking of T3, T2 and T1 causing the lights to turn off abruptly.
In this case, the interior light goes out quickly.
Time delay can be adjusted by potentiometer P1.

Circuit Diagram: 
Electronic timer circuit with transistors

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