This circuit is from a 1968 documentation. It makes use of thermistors (NTC) to indicate overheating of charged batteries. Modern equivalent components can be used.
This circuit was found in a 73 magazine for radio amateurs of the 90s. The circuit uses two types...
Found in a 1993 Electronics Experimenter Handbook, this circuit uses a multimeter to measure...
This powerful siren is suitable for warning or alarm systems. The components are current and the...