MOSFET circuitry

So I went to Segor, the local electronics store, and asked for some advice how to the switching on and off. The guy behind the counter was really nice and recommended the IRLD024 (costing 70 eurocents a piece; probably cheaper if I get 10 or more) and said I could use them both for the 3V (lasers) and 12V (el-wire). He drew me the pin description, and I went home with two of them (and all of the other stuff I bought) to try them out.



At home, I set to work. The laser was easy: connecting the PIC output to the gate (G), the ground to the source (S) (ground both from the PIC as well as from the laser), and the other side of the laser button to the drain (D) was all there was to it.

The EL-wire was slightly more difficult. I first tried putting the MOSFET in between the 12V of the DC input to the box to the 12V of the input to the invertor, but this didn't work. So I ended up with this working connection:
PIC output to the gate (G)
GND (board) to the source (S)
GND of the power input to the invertor to the drain (D)

So, in the coming week, I need to get more, so I can make these switches for the other laser and for the other EL-wire boxes.