Solved! What is Center Pin on HP Laptop Power Supply Plug

[Michael2000]

I was wondering what the center pin is used for on the HP Laptop power supplies. The outside barrel appears to be ground, while the inside is +19 volts. The center pin measure 14 volts unloaded. It appears it could be some sort of feedback loop, but I am not sure what for. Anyone know?

Michael

 

[tigerzntlworld]

I was wondering what the center pin is used for on the HP Laptop power supplies. The outside barrel appears to be ground, while the inside is +19 volts. The center pin measure 14 volts unloaded. It appears it could be some sort of feedback loop, but I am not sure what for. Anyone know?

Michael

This pin is used to identify that a HP adapter is being used and not a
3rd party one.It is wired to some sort of DC signal input on the motherboard.

Vic from UK.

 

[Michael2000]

This pin is used to identify that a HP adapter is being used and not a
3rd party one.It is wired to some sort of DC signal input on the motherboard.

Vic from UK.

Thanks, Vic for the reply. This is a real mystery. How did you find this out? Couldn't a third party one provide the same signal?

Michael