This circuit is from an August 1984 Radio Electronics magazine. It monitors the state of a RAM backup battery. Resistor R1 determines the battery charge.
This circuit shows how a monostable can be obtained from an RS flip-flop using a unijunction...
This circuit was found in an application note of the LTC1164 from Linear Technology of the 1990s....
Using a general-purpose transistor this AC amplifier was found in the November 1993 issue of...