Circuit simulation

[MysticZ]

Does anyone know of any decent circuit simulation software? I'd prefer
something I don't have to spend any cash on since I'll only use it
occasionally. I'm working on a little project to see what I can figure
out about strange logic circuits before I dive into the EFI setup for
the Ninja. This is just a little box that has 3 audio inputs: radar
detector, CB, and tape/radio (a Rio in my case), and one output for
headphones (or more specifically helmet speakers since this is for a
motorcycle). The radar detector input has the highest priority, the Rio
input the lowest. If while riding along listening to the Rio, the radar
detector goes off, the input from the Rio is disabled and the radar
detector takes over. Get the idea? So far I've come up with a circuit
using AND gates and inverters but the truth tables keep coming up with a
couple of errors and I need a way to simulate it before I hunt down the
components. Since I'm at least a little sane still I plan on using
optoisolators to keep strange things from getting to the goodies plugged
into the inputs and frying them.

Once I figure out how to make this work I'll be one step closer to the
EFI setup. Anyone have an idea?
-- 
Steve
97 Chevy Camaro Z28, Mystic teal, A4, not stock
90 Kawasaki EX500A4, black, M6, not even CLOSE to stock!
lt1_z28 at ev1.net  http://users.ev1.net/~lt1_z28
Aluminum, steel, carbon fiber, titanium, and two cast iron balls.
McMillan Motorsports- http://www.mmsbikes.com
----------------------------------------------------------------------------
To unsubscribe from diy_efi, send "unsubscribe diy_efi" (without the quotes)
in the body of a message (not the subject) to majordomo at lists.diy-efi.org