This filter, with a cut-off frequency of approximately 1 kHz, has a high Q and employs two operational ones. The power supply must be symmetrical.
This well-designed sinusoidal oscillator by Wien bridge was found in ancient European...
This is a circuit for testing small lamps and LEDs. The lamps that can be tested are the ones...
Found in a Popular Electronics from the 90's, this circuit can be implemented with almost any...