[Elecraft] Small 5 amp supplies?

[Don Brown]

Hi

Look at:

http://mouser.com/specsheets/55265U.pdf

I haven't tried the 60 watt but the 45 watt power supply works and is ver=
y quiet. These are laptop computer adaptors. The 12 volt will supply 5 am=
ps and the 15 volt will supply 4 amps. The 15 volt is a better choice if =
you have the internal battery option. Installing a 3 to 5 amp diode in se=
ries will drop the voltage to 14.3 volts just about right for charging th=
e battery.

If you are thinking of adding the KP-100 look at the MFJ 25 amp switcher.=
 I have a Astron 25 amp switcher, a MFJ 25 amp switcher and a MFJ 45 amp =
switcher. I like the MFJ's better than the Astron. They have lighted amp =
and volt meters, a cigarette lighter socket on the front panel and can be=
 adjusted from the front panel from 9 to 15 volts. The MFJ comes with a s=
chematic diagram. Astron does not provide diagrams and the voltage adjust=
ment is internal requiring the cover to be removed. Looking at the schema=
tic I can see why the MFJ's are so quiet. The supply runs in a resonate m=
ode rather than a switching mode, supplying a high frequency sine wave to=
 the transformer so the high frequency hash is eliminated in the LC circu=
it. The same as in a class C transmitter just at a much lower frequency.

As usual I have no interest in Astron or MFJ - JMHO :-)

Don Brown
KD5NDB
----- Original Message -----
From: Charles Greene
Sent: Tuesday, April 02, 2002 4:48 AM
To: John McClain
Cc: K2
Subject: Re: [Elecraft] Small 5 amp supplies?

At 07:15 PM 4/1/2002 -0700, John McClain wrote:
>Can recommend a very small 5 amp and electrically quiet supply that I
>can use with the K2 when I travel?  I would prefer a small switching
>supply even though the manual warns against it because of noise.
>
>John,

Morse Express www.MorseX.com sells a very fine, quiet, tiny 3 A switcher =
I
use for my K2.  Works very well.

73, Chas, W1CG


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