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.
This circuit is from the time when photos were revealed in darkrooms. We found it in a 1968...
This high-gain circuit was found in an American publication from the 1990s. The circuit can use...
This circuit provides an output of 5 to 10 V at its output from inputs of 1.5 to 4.5 V. The output...