Found in a 1990s US publication, this alarm circuit detects when a light beam is interrupted. Optical resources may be used for the sensor and instead of the alarm a relay may be used.
This circuit for PC and which can also be used with microcontrollers was found in an English...
This two-tone decoder has a bandwidth of 24%. The circuit is from a 1994 Electronics Now. The...
The LMV321 is a low voltage operational amplifier from ON Semiconductor. The following diagram,...