In semi-automatic washing machines, both the wash timer and the motor commutator use a mechanical time switch that can be damaged after a period of time. The washing machine electronic timer can replace the above mechanical timing switch.
The electronic timer circuit of the washing machine is shown in the figure. IC1, VT1, K1, etc. form an electronic time switch to control the washing timing of the washing machine. The monostable circuit consisting of IC1 (1/2 double D flip-flop CD4013), resistor R4 and capacitor C3 determine the monostable time, that is, the timing time. The circuit timing of this example is 40min. The switch SA is modified from the timing switch of the original washing machine. When the tool position is directed to the 1st end, the timing starts. At this time, the Q end of IC1 is high level, VT1 is turned on, K1 is connected, Contact K1 is closed, power is supplied to the motor control circuit, and the motor rotates. During the timeout period, the SA can be dialed to the 2nd end at any time to reset the circuit and stop the timing.