vollmster
commented
6 years ago I know it's been a while since you asked this, but in case you didn't figure it out on your own, the datasheets on each MOSFETs have the information you're looking for.
As for the transistor on the breadboard, if that's the one you're interested in, it's not a 2N7002 (which is a surface mount part).
The closest through whole equivalent would be a 2N7000. In it's case, viewed from the front, left to right, the leads are SOURCE, GATE, DRAIN.
However, the MOSFET in the breadboard image isn't a 2N7000 (which doesn't have a visible heatsink). On a through hole transistor of this style, (3055VL works for example), the pin layout viewed left to right from the front, is GATE, DRAIN, SOURCE.
For the breadboard image, the MOSFET shown has a layout of GATE, DRAIN, SOURCE (like a 3055VL). So the 2N7002 is just a label for illustration.
If you're building an equivalent circuit of your own, just keep this in mind:
GATE: has the 200 Ohm resistor in line DRAIN: goes to Bus pin 5 on the Wheelwriter and D3 on an Arduino SOURCE: goes to Ground on the Wheelwriter and Arduino
Anyways, if you hadn't solved this already, I hope it helps.
On your image of the breadboard matrix with the 2n7002 with heat sink could you put a "S" "D" "G" over the proper pins for source, drain, and gate. I tried to load kcad? or whatever to view the schematic but can't due to memory problems. It would also be helpful to others in the same fix to do a screenshot of the schematic and post it as a simple .png so no cad software is needed to view it. I am afraid my skill level is not high enough to figure out the circuit without a schematic.
Thanks
Buddy Bell