Power/current question

[Cowboy67]

I have a power question. The formula for finding current if you know power
and voltage is P/E=I. I have a radio that is suggested to use a 15Amp fuse.
If I do the formula the current draw comes out to around 4Amps. What, If
anything am I doing wrong?

Here are the specs on my radio...

40 watts transmit power
13.8VDC Power.

So current should = +/- 3Amps.

Why such a big fuse. I would think a 5Amp fuse would be safer?

Thanks in advance!

Jim

 

[Russell Powell]

I'm assuming this is a 2-way radio? When you mention
40 watts transmit power, this sounds like the signal transmit
power and not total power consumption of the radio. You could
measure current drawn from the cd powersupply and multiply
by 13.8V to get radio power consumption.


--
sincerely,

Russell Powell

Artisan Components
SR. FAE - U.S. Central
rpowell@artisan.com
469-438-6589





"Cowboy67" <cowboy67111NOSPAM@yahoo.com> wrote in message
news:blvh47$2ejs$1@news3.infoave.net...

I have a power question. The formula for finding current if you know power
and voltage is P/E=I. I have a radio that is suggested to use a 15Amp
fuse.
If I do the formula the current draw comes out to around 4Amps. What, If
anything am I doing wrong?

Here are the specs on my radio...

40 watts transmit power
13.8VDC Power.

So current should = +/- 3Amps.

Why such a big fuse. I would think a 5Amp fuse would be safer?

Thanks in advance!

Jim

 

[JeffM]

Yup. Yer not including efficiency of the final, drive stages,
housekeeping, panel lighting...