Simple power-on delay trigger circuit

Working principle of the circuit: As can be seen from the figure, endpoint A receives the 12 V positive pole of the radio head
(there are two sets of power supplies in the radio head, one set of nearly 20 V power supplies to the main circuit of the whole machine, and one
set of 12 V stabilized output Sv supply CPU ), endpoint B is connected to the negative pole, endpoints elbow and IV
are connected to both ends of the machine's manual trigger switch respectively. Transistor VT, resistor, capacitor
C. The purpose of forming a delay circuit (the parameter in the figure is a delay of 10 s) is to give other circuits of the radio head
time to enter a stable state.