Circuit Test Program

[skeeterb]

Is there any programs out there that someone can use to mock up and test a circuit, before they go to soldering onto a circuit board? I have an idea for a circuit that is going to be used with a Hydrogen on Demand system, and I need to test the circuit to see if I have gotten the bugs out of the design of the circuit before I start soldering the circuit together.

 

[3v0]

It depends.
Take a look at Spice. There is a free version called SwitcherCad III.

 

[Papabravo]

Google Crocidile Physics. Never used it, but I have seen it referenced.

 

[skeeterb]

Crocodile Physics is more educationally oriented. I like SWCadIII but it doesn't have some of the components that I need for my circuit, and I cant figure out how to do that draw my own component bit. My circuit uses 3 relays to switch the different portions of the circuit on and off. Two of the relays are controlled by 2 different sensors on the Hydrogen on Demand cell and the other relay is a safety feature to keep the cell under control if the secondary switch fails in the "On" position

 

[skeeterb]

Circuit help

I have uploaded a picture of my circuit. Can anyone help me figure out the last portion that i need help with. The upper sensor turns on a light when the water level gets below it. and when it gets below the lower sensor, it turns off the pulse circuit and turns on the water pump to refill the cell with water. I was using relays to try to do everything but couldn't figure how to get my curcuit working, but I may try using an IC to control the different functions of the circuit. What would be a reccomended IC to use for my circuit?