This filter was found in an American publication from the 1980s. The circuit can be implemented with any operational amplifier. The power supply must be symmetrical.
This beat frequency oscillator was found in a 1980s documentation. The original FET has a grounded...
XTAL from 4 to 20 MHz can be used in this oscillator. The XRF choke can range from 10 to 100 µH...
Found in Popular Electronics this circuit uses common components to control an incandescent lamp with...