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Circuits designed by David Johnson,
P.E.
Last Updated on:
Wednesday, December 20, 2017 06:11 AM
Master Category List - Dave's Circuits
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More
Hour Meters,
Testers,
Piezeoelectric Circuits |
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MACHINE VIBRATION
TRIGGERS HOUR METER |
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 |
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Click on Drawing Below to view PDF version of Schematic |
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