The circuit shown uses an operational amplifier that is uncommon nowadays. The circuit was obtained in a 1994 Linear Applications Handbook by National Semiconductor.
The basic siren configuration shown in figure 1 activates a piezoelectric transducer and can be...
This circuit triggers the LED when the monitored battery voltage drops below 9 V for 12 V...
This lead-acid battery charger was found in a Popular Electronics from the 90s. The circuit has a...