This filter was found in a Texas Instruments manual based on an operational amplifier 741. Other operational can be used and, with the indicated components, the rejection frequency is 2 kHz.
This variable power supply circuit was found in a German publication from the 1980s. The circuit is...
This simple circuit for switching RF signals was found in an RF Design from the 90s. The circuit...
We found this circuit in a 1983 English magazine, but it can be easily assembled with the BC548 or...