Whoo hoo, just soldered up my first arduino shield (SparkFun MIDI shield) this AM and it works swimmingly well! Now, to the next part:
I'm hoping to drive a 24VDC solenoid from my Arduino. I've been looking at the schematic in the playground (http://www.arduino.cc/playground/uploads/Learning/solenoid_driver.pdf)and I have collected the 1N4004, a 2.2k-Ohm resistor, but my Radioshack doesn't have a TP102.
They do have a TP120.
Is there an issue with using a TP120? I saw reference to using it in the forums at http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1199778137;start=all; I can pick up the heat sink et al to use it. But I'm confused on how to figure the power formula. Throwing in transistors and resistors throws me for a loop.
So, to summarize my questions: can I use the TP120? If yes, how to I calculate what power is needed to drive the solenoid?