This module includes an optical pass key and has two digits. We found this circuit in a 1995 documentation. Power can be supplied with voltages from 7 to 20 V using the regulator or 5 V directly. More digits can be added to the original project.
An application for the previous circuit (CB109) is shown here. The central frequency is determined by C and...
August 2016 - It can be obtained from Mouser Electronics the new DC-DC PFM Step-Down XC9272 from...
This simple experimental circuit using only transistor produces a tone given by C1 and C2. Tone is...