Its been 30 years since my last Physics course so while I have the basic concepts I'm uncertain how to solve my current problem: I need to operate a pair of 12V solenoids (.5 seated amps, 4 watts each) with a periodic on/off cycle that gently ramps to full voltage (over about .5 to 1 sec) and then shuts off, repeating every 5-10 seconds (I'd love to be able to adjust this once my device is built and tested). It sounds like an RC circuit to me in theory but I'm lost as to how to proceed in reality at these voltage/amperage levels. I've looked into programmable controllers but this seems like over-kill for what strikes me as an essentially simple operation. I'd love any help or thoughts on where to go to educte myself on this topic. Thanks.