AC voltage measurement can be carried out by converting AC voltage into proportional DC Voltage using rectifier and filter circuits. For low AC voltage (mili volts) measurement precision rectifier is used as diode knee voltage is 0.7 Volt. Similar to DC voltage measurement Voltage divider is constructed using 47K Ohm variable resistor R1. 5V zener diode is used to protect Arduino from accidental excess voltages. Adjust the resistor R1 (47K) to calibrate the voltage. Here the AC voltage that we can give to transformer is from 50V to 230V depending on its ratings. Rectified DC is fed to the voltage divider circuit. Continue reading AC Voltage Measurement using Arduino →