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.
The circuit is suggested by National Semiconductor in its 1994 Linear Applications Handbook. The...
Found in a 1969 Electronics World, this circuit is intended for amplifying analog cable TV...
Found in an Electronic Design from the 90s, this circuit uses a component of the time, difficult...