I'm more of nuts and bolts type of guy. When I get an idea I try to figure out how to do it. When I find out how to build it, I do it. Then I bench test them, if they work I move on with it. I'm looking a 555 timer circuit that I can adjust the on/off time. I want to see if the SSR I'm looking at will hold up as the manufacturer says it will for what I want to do with it. Do you know where I can find a diagram for this? I want to power the 555 from a 12VDC source and trigger it from a 5VDC source. I want to generate a pulsed 5VDC signal that will operate the SSR in the 1s to as fast as a 2ms range. Max amp rating for the input needed is 12ma for the SSR. I'd like to be able to adjust the speed. I do own an oscilloscope and can figure out how to check the signals. An even on/off pulsed signal is what I'm looking for. If you can help or send me in the right direction it would be helpful. Thanks and keep up the good work on the website, it's an inspiration.