HELP with P channel MOSFET.?

i've got a P MOSFET to connect some LEDs to 5v, regardless of where I connect the gate, the MOSFET (and the LEDs) always stay ON.
Iv'e tried connecting the gate to 5 volts (on the source), to the drain, even to a higher voltage (13v) and nothing, current keeps passing through.
I have checked my connections and pinout diagrams and they are all correct, but i thought that the MOSFET would let current pass when the gate was connected to Gnd and block it when it was connected to 5v (same as source), am I wrong?
please help, i'm lost and i have found nothing useful on the web.

PD i'm trying to control it with an arduino, and I have had no luck whatsoever.

johnpoole4 years ago
if all your test are correct then the mosfet is bad... with zero v on the gate.. source to drain should be open in one direction... because it is fet it has a diode between drain and source..
aelias365 years ago
Are you sure you have the right pins connected? Pin mapping isn't standardized, so look up the part number of your MOSFET to see if the pinout is what you think it is.
Emiliano Valencia (author)  aelias365 years ago
yes, i've checked in 3 different datasheets and all are the same.