Electrical – Current transformer for current sensing at Low Voltage AC

currentcurrent measurement

I have 230V/50HZ AC to 12V/5A step down transformer. Is it possible to measure the current at the secondary (Low Voltage AC)side of the transformer?
is it possible to use regular CT coil(which is used to measure the current @230V AC)

Best Answer

Measuring the current on the secondary side of the transformer can be accomplished in three possible ways.

  1. place a small resistor (less then 1 ohm) in series with the transformer connection and measure the AC voltage drop across the same. Thereafter it is simply Ohms law (I = V/R).

  2. The other way is placing a miniature current transformer (see picture) and measure the voltage across the transformer load resistor ( Do not use such a transformer without a load resistor). Look at the data and application sheet of such transformers for further information.

enter image description here

  1. A third way could be to use a hall effect sensor with corresponding electronics such as the NA25 or NAP25 both from FW BELL.

enter image description here