This circuit was published in the July 1993 issue of Electronics Now magazine. It uses a sensor from the time and triggers a buzzer with a Sonalert-type oscillator.
The audio signal generated by the oscillator stage is amplified by an LM380 and reproduced with...
This old integrated amplifier is from a Japanese publication from 1972. The integrated circuit is...
This second-order low-pass Salen-Key filter was obtained from an American 1980s documentation. Formulas...