This circuit for very long-time intervals was found in the March 1993 Radio Electronics magazine. Times of several days or even weeks can be achieved depending on the value of C1.
This circuit is an excellent application for the PIC in audio, but the reader who intends to do...
To a 16-0hm load, this amplifier provides a power of 10 W. We found this circuit in a Motorola...
This reader with TTL logic compatible output uses an LM139 comparator. The circuit was found in...