Non-Invasive Voltage Measurement Technique for Low Voltage AC Lines

A voltage measurement technique without direct contact to the electric line is described here for making an effective and safe way of voltage measurement which is useful for various electrical works. This non-invasive voltage measurement technique consists of a capacitive probe which works as a voltage sensor from the phase line. The analog signal processing block was built using the Darlington Pair method and cascaded NPN transistors to amplify the sensed voltage to a significant value. Finally, we built our empirical results into a graphical representation of output voltage from the circuit which indicates a proportional behavior of output voltage with the line voltage.