This circuit was found in 1980s American documentation. The transducer is a piezoelectric capsule and the power supply voltage can be between 3 and 18 V.
This RCA / GE circuit from the 90s can be applied to any modern operational amplifier. The number...
Found in Popular Electronics from the 90s, this circuit turns off an appliance at the end of the...
Found in documentation from the 90s, this circuit is based on operational amplifiers of the time....