
The
July 2009 edition of
WorldRadio Online magazine's
Trail-Friendly Radio column, by
Richard Fisher, KI6SN, features details on a simple field-operation accessory that can spare the operator a ton of headaches caused by fried equipment, as well as a ton of embarrassment.
This
reverse polarity protector can help you to avoid a reversal of fortune when out on the trail.
All it takes is inadvertently hooking up your battery cables backward:
POSITIVE lead to the
NEGATIVE battery terminal, and vice versa. The
WRO article has full construction details. Pictured here is the circuitry housed in a nice plastic box.
A
black power cable with large
alligator-style clip leads goes to the
battery. An
RCA jack with appropriate cable goes from the unit
to your transceiver.
With this accessory in line, if you mistakenly get battery polarity reversed, a protecting diode shorts the DC to ground and the fuse blows - saving your equipment.
Two spare fuses are wrapped in
white tissue and
stored in the box, ready to be called upon if any
knuckleheaded battery connections are made.
Here's the circuit's schematic:
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