On 08/31/2018 12:27 PM, doug wrote:
I just tested the 5 volt adapter I have. I connected it to a 12 volt power supply, and the output of the adapter to a CD Player with headphones. At the same time, I had an AM/FM portable radio
on the table about a foot away. Altho I have a fairly high AM noise level here, which I have not been able to find, the AM is perfectly clear, altho a bit noisy. I am about 60 miles from the New York City station.
There was no difference in the noise level with the power supply on or off. When on, I played a CD on the player, and it played clearly also. I then switched the radio to FM, and again, there was no
audible noise change when the CD was playing or when the power was off. Obviously, this is a linear voltage regulator design. (It should be noted that only one of the two negative input springs is connected.)
The power adapter has, as I mentioned, two USB jacks. It is marked "USAMS" on one side, and on the other side is marked in four lines, from top to bottom:
"INPUT 12-24 VDC
"OUTPUT 5V (polarity symbol) 3.1A
"10 CE <<<(the 10 is surrounded by two arrows in a circular pattern, one above, one below)
"MADE IN CHINA"
Hope this helps--Doug, WA2SAY