An electronic timer with alarm that uses very few electronic components can be designed using this electronic scheme. Asynchronous binary counter with 14 stages, 4060 type, has built in an oscillator with good stability in operation, a relatively wide frequency range. In the electronic diagram below oscillator frequency is determined by an external RC network connected to pins 9, 10 and 11.
When the circuit is powered through S1, impulse of the junction of R4 and C2 counter resets and starts counting.The time is set by P1. To achieve intervals between one minute and two hours, components oscillator need to do proper sized. For 1-30 minutes: C1 220nF P1 500k, 1-60 minutes: C1 470nF P1 500k, 1-120 minutes: C1 470nF P1 1M.