I have a load (from 20 LEDs with 20 resistors) that I want to switch on/off as a single block, using a GPIO pin from a micro-controller.
I have measured the current to be 145mA at 3.3V Vcc.
I have tried switching this load using two methods:
Attempt A: N-channel mosfet
When I switch the load on with a 2N7002 N-channel mosfet, I see that only 86mA makes it through the switch.
I also tried the 2N7000 N-channel mosfet, and I see 90mA for that.
Attempt B: Darlington Array
I tried switching it through the ULN2003 darlington array, using just 1 of 7 channels, I see a measly 64mA makes it through. (Coincidentally, this part seems to be sold-out everywhere, so I cannot use it anyway.)
Am I wrong to expect more current when switched? Did I use the mosfets or darlingtons incorrectly?