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By stonehayden
#195732
The product I am having trouble with is as follows: https://www.sparkfun.com/products/11214

The schematic and board layout are very confusing. Currently, we are simply trying to use the MOSFET as a switch. We are putting a logic high from a MSP430 onto the gate, have a 9V battery on the drain, and would like that 9V to output to the source to go across a relay coil we have as part of a project. The problem we have is that the source is always seeing the 9V from the battery and when the gate is disconnected, the source still has 9V. I believe we simply don't have the layout of the board correct and therefore are having issues. If someone could explain the layout of the board or how to accomplish the switching using this MOSFET that would be greatly appreciated. Thank you.
By n1ist
#195740
Connect the MSP430 to IN+
Connect the MSP430's ground to IN-

Connect the battery's positive terminal to OUT+
Connect the battery's negative terminal to IN-

Connect one end of the relay's coil and the cathode of a 1N4001 or similar diode to OUT+
Connect the other end of the relay's coil and the anode of the diode to OUT-