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 with only one transistor was obtained in an old English documentation and can be...
This circuit uses a transistor as noise source and a 741 IC as amplifier, sourcing a high...
This circuit uses an LED (called SSL) to regulate current in a configuration with complementary...