This filter configuration used in telecommunications uses 4 Jaumnann crystals that are interesting for low and medium frequencies. The circuit is from an 80's documentation.
This interesting circuit provides an output proportional to the input voltage, regardless of its...
The proposed circuit generates signals in the range between 9 kHz and more than 44 kHz, which, it is...
A modulated (intermittent) siren, using the four gates of the 4001 integrated circuit is shown in the...