As seen on the diagram, more powerful, sensitive and high gain transistors can be made by connecting the transistors together.
When the switch S is turned off in the given turn-on type time-delay circuit, the current C flowing through R1 and P starts to fill. When the voltage of C reaches a certain level, T1 transistor passes through. When T1 transmission passes, the transmission passes at T2 and the relay operates. If B is pressed, the C circuit breaks when C is discharged. So the buyer does not work for a while. After a certain time, they start working again.