This circuit for frequencies of 20 to 2 kHz was obtained in English documentation from 1966. The transistor can be any general purpose and powered by batteries.
Found in an Electronic Design from the 90's, this circuit uses an SCR according to the controlled power....
For the 1 MHz frequency, the pass band of this filter is only 120 Hz wide. The filter is suitable for...
We found this circuit in an English publication from 1995. The Hall sensor used is a component of the...