Long time timing control circuit (1)

Circuit working principle: IC. CD4060 is a 14-level divide-by-two counter with an oscillator.
The circuit inside pins 9, 10 and 11 of R2, RP, C2 and Ic forms an oscillator
. The oscillation frequency can be adjusted by RP. When we turn on the power, +9 V DC
charges c3, making TC. Pin 12 of the reset terminal is reset after power on, pin 3 outputs low level
, and the timer circuit starts to work; when the timer expires, lC. Pin 3 outputs
a high level , and this high level is a counting pulse of IC2. ICz is the decimal counting/divider
CD4017 , C4 and R. The branch circuit is a power-on reset circuit. After power-on, its counting output
terminal Q9 outputs low level, the transistor VT is cut off, and the relay does not work.
After the timing time set by CD4060 expires (according to the data in this article, it can be up to 16 hours), pin
3 of CD4060 outputs a high-level pulse, and this high-level pulse causes CD4017 to start
counting. When the CP terminal of CD4017 enters the 10th pulse, the Q9 output terminal of CD4017 outputs a high level, that is to say, the maximum timing time of the circuit can reach 16 x10= 160 h. At this time, the transistor VT is saturated and conducts, and the relay is powered to work, and its contacts can be used to control the work and stop of various electrical equipment.