My HP Pavilion 27C Monitor and my HP Notebook 15 both have similar types of AC adapter that supplies 19 volts, but they both have that third wire in the middle, also. I am measuring 0 volts on it, on the monitor supply.
Everything works great. I am just asking for advice on what kind of circuit I need to supply whatever signal that third wire provides. Or, even better, can I just ignore it?
I'm starting with a 24 volt battery bank connected to a solar power system that varies in voltage from 23 to about 30 volts.
The goal, obviously, is to convert the Pavilion 27C monitor to run on DC so I don't incur the losses of going through both the inverter and the AC adapter. And for times when the inverter is off, like at night.
I need to design a way to use this power for this device.
I have looked at many web sites that have intricate circuits but am hoping for something simpler that can handle the voltage variations nad still put out a pure 19 volts.
In searching around I found and bought this 24-to-19 volt regulated converter. Here is the link to the converter: 24-to-19 volt converter.
The 19 volts seems to be very steady so far. It actually seems to tolerate the whole voltage range the solar MPPT controller puts out to the battery bank.
So maybe the power supply part is going to be OK.
But what about that third center wire? I don't know what it does or what to do with it. I don't know what the devices want from it.
My HP laptop uses the same voltage and has the same plug with the same third wire in the center, and I would like to convert it also. But I will start with the monitor.
So my question is: What do I do about that third wire? Can I simply cut into the cable and provide power to the two obvious wires that are +19 and Gnd, and just ignore the center wire? Or, if not, what can I do to make this work?
Especially for the laptop, what circuit will I need to supply that third wire with whatever the laptop is looking for?