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 circuit was found in an American documentation from the 60's. The transistors are from the...
This oscillator is indicated for the adjustment of FI of FM radios, having its frequency...
This configuration triggers an external circuit or simply an LED for time given by R1 and C1 (T =...