• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

3 phase 3 wire measurement


New Member
Dear all,

I am trying to build 3 phase voltmeter that could measure L-L and L-N voltage during 3 phase 3 wire and 3 phase 4 wire connection. 3 phase 3 wire and 3 phase 4 wire connection are external connection.

as we know in 3 phase 4 wire we will get neutral reference so we can get accurate reading for L-L and L-N.
but in case of 3 phase 3 wire we dont have neutral reference .In this case it will be difficult to get gnd reference. I would like use both connection type in common circuit,

I have seen one of the product where they using V-X-M-H IC , can some one suggest me functionality of this iC. i have attached schematic for reference.

If any other suggestion with schematic will be appreciated. to differentiate 3 phase 3 wire and 3 phase 4 wire


Last edited:


Well-Known Member
Most Helpful Member
Can you just use some suitable resistors in a star formation to make a virtual neutral?



New Member
Dear sir,

I have attached some of circuit used and tested . I need help in to complete isolation and grounding part to MCU,
How can do this using differential amplifier circuit.
Circuit 1: purely based on voltage divider network and for delta connection. I wanted to use common circuit for both star and delta. how can i isolated the ground here.

Circuit 2: Using V-X_m_H ic OR TA1G label printed on it. i am curious to know what this ic will do??


Last edited:

Latest threads

EE World Online Articles