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.
August 2017 - New DTMOS Super Junction MOSFETS from Toshiba are in stock at Mouser Electronics....
This shield can be used both to interface microcontroller circuits or TTTL. The resistor in series...
Found in documentation from the 1980s, this circuit uses components from that time. The circuit is...