I have a 28volts AC source that I've like to be able to bring down to microcontroller usable DC level. I was thinking a bridge rectifier followed by a voltage regulator such as the LM317 or LM78XX.
My simulations show that AC at 120Hz at 28 volts, with a full bridge rectifer, 100 ohm load, and a 100uF filter cap produces about 19.5 to 26.5 volts on the output. I'm sure that the regulator won't like that and will echo these ripples on the output. I can go with a bigger cap, but I don't have any 10mF caps laying around that will filter that down to a reasonable DC level.
Can some one clue me in on how to bring down the variations here so I can run it through a regulator and into my uC.
Also, are there any suggestions on polling another 28volt line with a uC other than another bridge rectifier, BIG cap, and a voltage divider?