This filter was found in Exar documentation from the 1980s. The circuit has an attenuation of 60 dB at the selected frequency. The power supply must be symmetrical.
Found in Popular Electronics this circuit will trigger a buzzer if the ignition key is removed...
Found in Popular Electronics, this sophisticated short-wave receiver requires a lot of skill from...
This circuit is from an old American documentation using LEDs in the rectification. The circuit...