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
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