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DiscoverCircuits.com -- Hobby Corner
Last Updated on:
Wednesday, June 02, 2021 01:45 PM
Hobby Circuits List
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LINK to Dave's circuit, but DO NOT COPY any files to your WEB
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Single Lead-Acid Cell Voltage Monitor, July
7, 2012
designed
by David Johnson |
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The circuit below uses a a low voltage reference and a voltage
comparator from National Semiconductor to monitor the battery voltage. The green LED is controlled by a tiny charge pump type voltage
converter IC from Texas Instruments. This device efficiently converts the 1.8v from
the battery into 3.3 volts. A dual Schmitt trigger inverter IC, also from Texas
Instruments, was used to latch the normal and low battery states and a Honeywell Hall
switch was used as reset switch. A small magnet held to the side of the plastic
module holding all the parts would unlatch the alarm condition.
When everything was
working properly, a bright green LED light would turn on. If the battery voltage
were to drop below 1.8v, the green light would switch to red and stay in that mode, until
reset with a magnet. The complete system was housed in a small plastic box, less
than a cubic inch in size. Epoxy was used to encapsulate the circuit components. |
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Click on Drawing
Below to view PDF version of Schematic |
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DC Magazine, 3rd Quarter, Page 7: Single Lead-Acid Cell Voltage Monitor |
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