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 shown allows the test of common silicon diodes. The characteristic curve of the...
The connection of high-value input resistors causes the circuit to behave like a conventional...
Linear Technology's LT213 circuit, which suggests this application in 90s documentation, is not...