[Elecraft] Walwarts - linear supplies

[Victor Rosenthal 4X6GP]

I've added regulators and (when needed) rectifiers to wallwarts. I just 
put the components on a piece of perfboard, cut the wire, hook it up and 
tape the board to the wart. Presto, a regulated linear wallwart.


73,
Victor, 4X6GP
Rehovot, Israel
Formerly K2VCO
http://www.qsl.net/k2vco/
On 21 Nov 2017 10:43, Jim Brown wrote:
> On 11/20/2017 5:50 PM, Brian Hunt wrote:
>> Be careful using the non-regulated linear wall warts. The open circuit 
>> voltage can be more than 16 VDC and could be harmful to gear not rated 
>> that high.
> 
> Yes and no.  The vast majority of linear wall warts are UN-regulated, 
> but the current drawn by the equipment being powered significantly 
> reduces the output voltage, usually to the rated value. That's how 
> linear, unregulated power supplies work. That's why it's good to match 
> both rated voltage and current. AND -- most equipment will tolerate 
> moderate over-voltage. The K3, for example, is rated for 15VDC max.
> 
> And, or course, not all gear runs on 12VDC -- lots of stuff runs on 5V, 
> 7.5V, 9V, and 14V.
> 
>> Best to measure OC first!
> 
> Measuring OC is a good thing, and EXPECT to see 25-30% higher voltage 
> than rated. But what matters is the voltage under load. And that's why 
> my applications note recommends putting Power Poles on both the wart and 
> the connector to the equipment, then sticking a voltage monitor in line 
> with the equipment connected. You did read the link I posted, didn't 
> you?  :)
> 
> 73, Jim K9YC