If i wanted to measure and display 120VAC (Voltage, Current, Power, AC Wave, etc...) from a receptacle in my house using a PIC16F877A. What would be the most economical and simplest approach? This is for a class project so I was just curious.
Use rectifier, then the divider. If you want to show the full waveform on some graphic LCD, then don't use rectifier, but you'll need to finetune the divider to get best results. I sugget to use 1:100 with 87k and 1k fixed resistors and 20k multiturn pot.
This is AC voltage so simple divider will not be enough. You'll need some level shifting as well because the A/D converter in PIC cannot measure voltages below ground (Vss).
This is AC voltage so simple divider will not be enough. You'll need some level shifting as well because the A/D converter in PIC cannot measure voltages below ground (Vss).
We made a measurement AC with voltage-frequence converter on AD654.
Next one is optocoupler 6N137. Microcontroller PIC measure period imulses.
Low cost and simple.
If you don't know much about mains voltage stuff and you don't know how to build a voltage divider then you have a good chance of hurting or even killing yourself and at the very least setting teeny weeny parts on fire. Line level AC can kill you. Hit the books first, I can't imagine your instructor didn't warn you first.
Try experimenting with 6.3VAC (using a AC wall adapter) till you get a grasp of the concepts involved.