Appliance on-off timer with LM555 and CD4020B

Thread Starter

moondust

Joined Apr 25, 2026
3
I have to build a cyclic timer that automatically toggles an appliance on and off every 2 hours. I decided to use CMOS logic for this build. The circuit uses an LM555 clock generator to provide the base pulses for a CD4020B 14-stage binary counter. But I can't find similar projects. Can anyone steer me in the right direction?

P.D. I believe a CD4060 would be a better option but I wanna stick with the 4020
 

MisterBill2

Joined Jan 23, 2018
27,187
As for the CD4060, I have had problems getting that internal oscillator to function. So I suggest staying withthe CD4020 binary counter. The 555 is a TIMER IC, NOT a clock generator, although it certainly can be used for that purpose.
Switching an appliance will probably require switching mains voltages at some current level. So you should consider how you will isolate the CMOS section from the mains voltage. THAT is important.
 
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