I have a positive-triggered, 16ch relay board that draws 3.8mA (measured) at each control input when the input is ON (High). The driver on the relay board is a darlington pair IC. I need to turn on 7 relays at once using a single PICAXE output pin. Obiously 7 x 3.8mA exceeds the 20mA max per pin current and, as you might imagine, it doesn't work correctly. I'm trying to figure out how to make this work with the limited components I have on hand. I have some 2N7000 N-channel FET's and I tried using a low-side switch circuit but it wouldn't source enough current through the pull-up resistor on the FET's drain. I know I could use a relay but I don't have one on hand and I'm out of room on the prototype circuit board.
Anyone know of a circuit using N-channel FET's that will work? I am open to ideas.
Anyone know of a circuit using N-channel FET's that will work? I am open to ideas.