DELAY FOR INTERIOR LIGHTING

Now, almost all modern cars have a delay circuit on the interior lighting circuit. This allows you to get in the car and close the door as soon as you close the door and see the left and right inside the car for a while, and most importantly, the ignition key hole
you find it more comfortable. The circuit is extraordinarily simple.

When the car's door is opened, the contacts of switch S1 (where switch S1 is the door contacts) are closed, in this case the base leg of the BC337 transistor falls to ground potential and the transistor is not in transmission. The capacitor C1 also charges quickly through the R1 resistor. During charging, BUZ74 is in transmission and the internal light is on. When the door is closed, the S33 switch will open and BC337 will be transmitted and the C1 capacitor will be uncharged. Thereupon, the capacitor C1 is gradually discharged through the R2 resistor, which ensures that BUZ74 remains in the transmission and the interior light gradually darkens. This is all.
You can adjust the charge and discharge times by playing with the values of R1, R2 and C1. You can mount the circuit on perforated pertinaks and place it in a space inside the ceiling lamp.