Transistor Switching I'm hoping that someone will be able to help me. I'm looking to produce a power interrupt for testing. I'm looking to have 28V DC input flowing to an output which I can hook up to a load and then switch on and off using an Arduino. I'm thinking of using an NPN high current transistor, I have built the box and code which runs fine. The issue I am having is the pin output on pin 13 doesn't have enough current to switch the transistor, can anyone recommend a transistor that would be able to take the high current and be switched by the Arduino? If you would like a schematic to help you understand it I can provide one! 

Thanks for reading,
Lewis
If you did manage to switch the transistor on, It would only output 4.3V, the rest would be dissipated in the transistor. If you managed to switch 4A this would dissipate 96W - and the transistor would melt.

A MOSFET would be a better option and could be easily switched by the Arduino. (I regularly switch 10A using a MOSFET and Arduino.)

This assumes you can put the MOSFET in the negative lead. If not you should use a P-Channel MOSFET, but you need a more complex circuit to drive it.

Have you considered using a relay module?