Dead MOSFET in RC Switch?

I was just wondering the best way to tell if I have a dead MOSFET. When I switch it with no load connected, I see the voltage increase (one or two volts less than the supply). But when I put any load on, there is no increase in voltage, even with a very small load.
I am using the medium low-side MOSFET switch, and have not had it operational yet, so I don’t know if I damaged it while soldering wires to it, but I wouldn’t have thought so. Also, all the LED indications work correctly and I cannot see any visible damage.



Can you provide a diagram or picture of your setup? What voltage are you talking about? Keep in mind that the output changes between ground and floating, so you won’t get much of a meaningful measurement from looking at just that voltage relative to ground. If the LED is behaving correctly, I am optimistic that the board is still okay since the MOSFET should not break that easily just from your soldering wires to it.

- Jan

I have it installed in my RC helicopter at the moment, but will try to get it off tonight (NZ time) and post a picture with details.
Now that I think about it, I may have wired my load (electromagnet) between the output and GND instead of the output and Load supply, which should explain the voltages I am reading (I measured these at the electromagnet since I covered the switch with heatshrink).

To answer your other question, I am running the logic from a 6V supply through two diodes to reduce it well below 5.5V and switching about 8V (2cell LiPo).

I will update with more info soon. Thanks

Looks like I did wire it up wrong. I don’t know what I was thinking.
Thanks for your help though.