Ok, thanks for check out my question.... I want to make a multimeter using a microcontroller and a 12 or 16 bit ADC. So far all I have been able to do is use a voltage divider (2 resistors duh) and measure 0-20vDC by dividing the voltage in question by 4 and it was spot on however when i tried to create one that divided by 20 so I could measure up to 100vDC the smaller voltages were off by 2 volts or more. I assume what i need to do is somehow choose the correct voltage divider based on the voltage we want to measure but I dont want to have a selector switch I would like to make the circuit autoranging. Any simple schematics available? Can anyone help me?