Hi,
I need to measure only voltage at 120VAC/50Hz power line using micro-controller built in ADC 12-bit whose input rage is 0-2.56V. I have a rough idea of using a resistive/capacitive divider circuit to lower the 120VAC to 2VAC. But what i really don't understand is whether the output of divider network will swing between -2 to 2 VAC or 0-2VAC. If so do i need to level shift it using a 2VDC or use a Diode to remove the negative swing.
Requirements:
Should be accurate +-0.2V
I'll be calculating the RMS value in the microcontroller and transmit it to PC via RS232. The sampling frequency is 400Hz.
I need to measure only voltage at 120VAC/50Hz power line using micro-controller built in ADC 12-bit whose input rage is 0-2.56V. I have a rough idea of using a resistive/capacitive divider circuit to lower the 120VAC to 2VAC. But what i really don't understand is whether the output of divider network will swing between -2 to 2 VAC or 0-2VAC. If so do i need to level shift it using a 2VDC or use a Diode to remove the negative swing.
Requirements:
Should be accurate +-0.2V
I'll be calculating the RMS value in the microcontroller and transmit it to PC via RS232. The sampling frequency is 400Hz.