[Elecraft] Walwarts - linear supplies

[Ron D'Eau Claire]

I have a several linear wall-warts that I collected over the years which I guard jealously. 

However a few of them are only a transformer and provide low-voltage AC to the equipment. The rectifiers were included in the item being powered. 

73, Ron AC7AC

-----Original Message-----
From: elecraft-bounces at mailman.qth.net [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Jim Brown
Sent: Monday, November 20, 2017 1:42 PM
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] Walwarts - linear supplies

Older wall warts are linear.  If you're smart enough to have saved them, there's a good chance you won't have buy anything.  Simply select one with the matching voltage and rated for the needed current, cut the cables to both old and new warts, splice the old wart to the connector that mates with the unit you need to power.

Older warts are often available at second hand stores and flea markets. 
$1 is the going rate. In general, linear warts are much heavier than SMPS units, so that's a good first check. A better one is to plug it into AC and hold a portable radio next to it tuned somewhere near 2 MHz (like the top of the AM BC band). If you hear hash, it's a switcher. If you don't., 99% chance that it's linear.

All of this is described in http://k9yc.com/KillingReceiveNoise.pdf

73, Jim K9YC

On 11/20/2017 1:17 PM, Joe Subich, W4TV wrote:
> All Electroncs (www.allelectronics.com) has analog wall warts of 
> various voltage/current capability depending on what is available in 
> surplus at any given time.  One may not even need regulated voltage as 
> many devices contain internal regulators ...


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