[Motorcoach1]

Circuit simulator and design tool link. I use this tool to help design circuits before I buy anything. This will test the circuit and you can make changes where nessary. It will show paths and function and theee is a test pannel at the bottom , occillascope and other tools it's free. so before going and buying a bounch of parts and boards you can test it here first. http://www.falstad.com/circuit/directions.html Please keep and share this link it is most valuable in designing and prototypeing . Mike

[CountZero]

If you want a free spice simulator you can check out LTspice: http://www.linear.com/designtools/software/