This window comparator circuit was found in a Popular Electronics from the 90s. The circuit has a multiple adjustment input network to determine the operating ranges.
This circuit is from the National Semiconductor 1977 FET Databook. The FET can be BF245 or MPF102...
This circuit was obtained in a 1967 Electronics World. The components are still common today, the...
This circuit uses a piezoelectric transducer to produce sounds like a buzzer. Frequency is...