This circuit was obtained in an Electronics Now from the 90s. The circuit uses operational amplifiers from the time and the indicator is of the Sonalert type with internal oscillator.
This 1967 Electronics World circuit is suitable for frequencies up to 1 MHz. The setting applies...
This circuit allows linear brightness control of an LED from an input voltage. The power supply must...
This circuit was obtained from my Mechatronics Sourcebook, published in the United States. In it...