[NLRS] Power Poles

[Dr. Gerald N. Johnson, electrical engineer]

With automotive cube 30 amp relays under $4 each, you can protect the
PAs using a relay. Hook the relay contacts between the power in and the
load. From the power in wire hook a diode, cathode to the relay coil.
Hook the other relay coil to the negative return. The relay will only
pull in with proper polarity. If you want to be sure not to fry the
series diode from inductive kick from the relay coil, add a back biased
diode across the relay coil. Then you have double diode polarity
protection.

For the 10 amp loads, Cinch-Jones P306CCT plugs are only $3.07 each and
the matching panel jack J306AB are only $2.19 each in the latest Mouser
catalog. More or less at Radio Shack, if they still carry them. Often in
the quarter bins at hamfests.

73, Jerry, K0CQ

-- 
Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
Reproduction by permission only.