Hi, I'm not actually an electrical engineer (shh!) but I'm trying to do some circuit design to save our lab a little bit of money. We're looking to count triggers from a discriminator in a NIM crate. I've put together a prototype pulse counter on a bread board using some 74190 divide by ten counter chips, 7447 BCD display drivers, and some seven segment displays. Right now, it counts up to 99 (two digits) and for the experiment we're looking to count up to 7 digits which is going to be really simple now that I know how to chain the counters together. Now, I need three of these counters, so I think that a printed circuit board is going to be the easiest way for me to assemble them quickly and in a permanent fashion. I've decided to try to design this on my own (again to save money) and so I've tried using Diptrace. It's fairly intuitive and I've been able to design the circuit almost completely (I'm not sure what pin layout to use for the seven-segment displays I've got, part number LSD5061-11) but I want to make perfectly sure that the circuit will work as it is supposed to before we buy the PCBs. To do that, I'd like to design the circuit in some CAD software that I can use to test it, then use that design to automatically generate a PCB. So, is what I'm trying to do even possible? I'm very new to the world of building circuits with chips, this is only my second time really dealing with them so it may just be a fantasy. If something like this does exist, I'd prefer it to be freeware that can run under Linux, any and all alternatives are possibilities. Thanks in advance for your time!