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 was obtained in a 1990 English magazine. The circuit can be assembled with equivalent power...
Varactor diodes are our varicaps of today. This circuit for switching signals in an RF circuit was found...
This basic circuit was found in RCA / GE documentation from the 90s. In it we have the way to...