Got a couple pic16f819s and was pondering something relatively simple like a voltage meter or a frequency counter. My question is the MC I have comes with an ADC that seems to max out at 5 volts. This seems to mean that I couldn't test for more than 5 volts. For instance I could test a 9 volt battery even with this thing. That seems pretty weird but I leave that alone. I come from a computer background and have some year of experience pouring over poorly written documentation. Having said that the literature for electronics is pretty rough to understand. Take the ADC on my pic16. The way it would be intuitively used would be to take a certain voltage and then send an analog signal (voice or radio) on that voltage. The output would be some digital representation of the analog. This already is terribly confusing. There are an infinite number of possible analog values for any length of time. How then does the IC map this onto a digital value? Moving on. How does the ADC know whether it's measuring voltage, current or some signal? Many on the internet suggest you can use an ADC as a voltmeter or an ammeter. Great but how does the IC know which it's supposed to be using, the signal the current or the voltage? Heres the PIC page: http://www.dimensionengineering.com/appnotes/Gmeter/PIC16F818.pdf You can google ADC voltmeter, ammeter, signal converter etc and find tons old projects.