In the first circuit we see how two different modes of ICs can be coupled together to form an effective long duration timer circuit. For getting 24 hour, or even days and week intervals you will have integrate a divider/counter stage as shown below. Unless these IC are integrated with another divider counter device such as IC 4017, getting very high accurate time intervals may not be feasible. ICs like 4060, IC 555, etc basically generate oscillations which are adjustable right from a few Hz to many Hz. This inaccuracy is mostly due to capacitor leakage current, and inefficient discharging of the capacitor. IC 555 as a delay timer is even worse, it's almost impossible to get accurate delays even for an hour from this IC. I have confirmed practically that beyond 4 hours IC 4060 begins deviating from its accuracy range. Please remember that you can never produce long accurate delays using only a single 4060 IC or any CMOS IC.
The time delay is set externally by the user as per the requirement.
A timer in electronics is essentially a device which is used for producing time delay intervals for switching a connected load.
