This circuit, suggested by an Electronics World of 1969, keeps a blinking LED for a while when a power outage occurs. Time depends on capacitor C1.
This indicator makes use of an LM339 voltage comparator circuit that contains 4 internal...
This two-transistor amplifier can be used as power stage for intercom, experimental receivers,...
This circuit is from an old American publication, using transistors of the time and operating with a 48...