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Alarm Circuits
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Click on Drawing Below to view PDF version of Schematic |
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UNPLUGGED POWER CORD ALARM
Many medical devices, such a portable X-ray and ultrasound equipment, carry their own batteries. However, the frantic pace of some hospital emergency rooms might cause the device to be shoved off into a corner without being plugged back into an AC power source to recharge their batteries.
So, I designed this circuit to emit an audible alarm whenever the device’s power cord was unplugged from the wall for a period of time. The device was designed to snap onto the outside of a power cord, where it senses the AC electric field emitted. No direct connection to the internal wires
of the power cord is needed. I also included a low battery voltage monitor. |
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Alarm Circuits
Master Schematic Category List - David A. Johnson, P.E. |
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