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Which fuse to use?

Sep 12th 2012, 00:48

N8FNR

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
I recently bought a switching gasafet ARR preamp for 70cm to use with a Arrow dual band handheld antenna to hear the downlink from the FM satellites. http://www.advancedreceiver.com/page7.html

The preamp draws 100ma at 12v and the wire I am using is 16 gauge and about 1 meter long.

I would like to fuse the positive line because I really want to protect the preamp and wonder what is the ideal fuse rating I should use?

BTW I went to Radio Shack today and the smallest rated fuse they had was a quick blow 1/4 amp for 250v.

Would it be ideal to use a blade type car fuse rated for 1 amp for my application as that seems the lowest rated commonly available one?

Any suggestions on this will be greatly appreciated.

Zack
N8FNR
Sep 12th 2012, 13:33

W1VT

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0

A 1A fuse near the battery is a good idea if the supply voltage somehow gets shorted to ground. Without a fuse, many batteries can dump enough current into the wires to start a fire!

ARR preamps typically have diodes for reverse polarity protection.

Zack Lau W1VT
ARRL Senior Lab Engineer
Sep 12th 2012, 19:22

N8FNR

Joined: Apr 4th 1998, 00:00
Total Topics: 0
Total Posts: 0
Thanks for the reply. I will go with the 1A fuse.

Zack
N8FNR

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