This circuit is from an old Mullard (Philips) manual with applications using the 555. Choosing appropriately the resistors and the timing capacitors, the ranges obtained can exceed days.
We found this circuit in a 1981 documentation. The circuit can still be easily assembled, as it...
This circuit was obtained in an old publication from 1979. It describes a simple low frequency...
This circuit was found in a 90's EDN. It can be implemented with either TTL or CMOS logic and used...