The integrated circuit can be any operational and T1 can be a BC548 and T2 a TIP41 in this circuit of a 1978 publication. What it does is feel a small voltage variation, given by the setting of R6 by triggering a time circuit that puts in Short the platinum avoiding the operation of the motor. So he feels when someone gets in the car or tries to start, immobilizing the car a few moments later. The circuit is for 12 V cars and the relay for the same voltage.
