On Mon, 16 Jul 2018 13:12:56 -0700, you wrote:
I've seen a standardization to several end destinations. One is that
the voltage rating seems to determine the size of the barrel
connector. That's now, from what I can see.
Secondly, there's a current limit that's also imposed. I have an HP
that wants higher current for the supply, and does not have the (older
standard) 5.5/2.1 (whichever *is* the "standard")) connector. It's
actually smaller in the barrel.
I'm going to conclude that there's an evolving standard out there, and
I have no idea of what it is.
Now, that is completely screwed up by the "DELL" standard, which
apparently includes some HP laptops.
Dell has a 3 wire cable to the power supply brick. The inner pin is
apparently an I2C connector. The inner and outer shells are power and
ground (suggest that the outer is ground). In a DELL computer, if the
power block does not identify itself as a "genuine" power adaptor,
then the battery will not charge.
Those adaptors (and don't ask me what I think of them) work with a
different standard. Not sure what the effective voltage and current
limits are in this case.
Bottom line, there *is* somewhat of a standard (don't know what it is)
that is now applied to barrel and pin diameters for different voltage
They do seem to be approaching some modicum of standardization finally. My sister had 2 laptops different brands and the power supplies were interchangeable, and my Gateway supply runs them as well. They are all about 19 volts and it seems the polarity has been matching. I noticed an older Gateway adapter would not work on my newer Gateway and I suspect it is because it pulls more current. Maybe not running but it might charge faster. The diameter of the whole thing is the same but the pin in the middle is larger.