High-precision 6-60 second timer

High-precision 6-60 second timer The timing time range of this circuit is 6-60 seconds. When switch AN is turned on, relay J1 is closed, and capacitor C1 is charged through R1 and potentiometer KP. When the voltage across C1 reaches 2/3 of the power supply voltage, the output state of the IC flips, completing the timing process. The function of the zener diode VW2 is to ensure the stability of the high value voltage when the power supply voltage changes ratio; VW1 is used to stabilize the capacitor charging voltage to further improve the accuracy. The timing time of the circuit is T=1.1(R1+KP)C1. By adjusting KP, any timing time within 6-60 seconds can be obtained. The voltage stabilizing diode VW1 is selected to be 8V, 1/2W, and VW2 is 6V, 1/2W.