I read that it is a weird poly switch (ptc) that provided some protection and a slow (rise) voltage on to the metal detector.
In line...I understand it prevents an in rush of current that could blow the fets.
HI
This is a thermal switch. It will open circuit when the temperature rises above the value of the device but will revert back to the closed circuit position when the temperature cools down below this temperature.
I thought it was a thermal switch, but someone said it possessed magical powers that prevented an inrush of current too. It measured a dead short until I exposed it to a heavy load and read open.
Thank you again. Its part number turns up nothing.