DiscoverCircuits.com, has 30,000+ electronic
circuits, cross-referenced
into 500+ categories. We have searched the web to help you
find quick design ideas.
We make every effort to link to material posted by the designer.
Please let us if you would like us to link to or post your
design.
The contents &
graphics of Discovercircuits.com are copyright protected.
LINKING to Dave's circuits is permitted but DO NOT COPY any files to your WEB
SITE server
This circuit allows an
off-the-shelf battery powered digital hour meter to be turned on and off,
according to a machine's operation, without requiring a direct electrical
connection to the machine. Machine vibrations are detected by an off-the-shelf
piezoelectric wafer. The wafer is normally used as a sound generator. The 3v power
could be tapped from the hour meter's own lithium battery or from a separate 3v
lithium battery. The circuit only draws about 1.5uA, so a 250mA-hr battery would
power the circuit for about 10 years. Published in EDN, Jan 16, 1997
Click on Drawing Below to view PDF version of Schematic
