What is a current transformer?

• A. A current measuring device
• B. A device that measures DC voltage
• C. A device that data to the microinverters
• D. A device that measures temperature

Answer: (A)

A current transformer is a device that measures AC current by magnetic induction while keeping the measurement circuit isolated from the high-current line. It passes the conductor through a magnetic core and uses a secondary winding to produce a scaled current that reflects the primary current. Because it relies on changes in current to generate the secondary current, it only works with alternating current, so it isn’t used for measuring DC. In PV monitoring, CTs provide safe, scalable current readings to meters or monitoring equipment, enabling accurate power and energy calculations. They don’t measure DC, they don’t measure temperature, and they aren’t devices that directly transmit data to microinverters.