How to Wire an Electronic Transformer

Updated July 20, 2017

Electronic transformers are smaller in size than their magnetic counterparts and can therefore be used in appliances with space limitations. Their lower cost is somewhat offset by their shorter lifespan compared to magnetic transformers. An electronic transformer has an inverter circuit that changes the AC frequency from 50-60 Hertz to a much higher value, such as 20,000 Hertz. Since output power depends on this frequency, electronic transformers are very useful in applications where power needs to be varied, such as in light-dimmer circuits.

Turn off the mains switch supplying AC voltage. If possible, turn off the circuit breaker supplying current to the circuit on which you will be working. The circuit breakers are found in the electrical cabinet that is generally installed in the basement or garage. There should be identification markings beside each circuit breaker. Find the breaker corresponding to the circuit you will be working on and turn the switch to completely disconnect the circuit from mains supply.

Identify the input and output terminals of the transformer. These are usually clearly marked as "AC IN" and "AC OUT."

Strip off the ends of two electrical wires of suitable length using the wire stripper.

Connect one end of the wires to the live and neutral wires in the junction box. The other end of the wires will be connected to the transformer input.

Connect the other ends of the two wires to the input of the transformer, using the screwdriver. Connect the live wire (generally brown or red) to the transformer terminal marked "L." Connect the neutral wire (generally blue or black) to the transformer terminal marked "N."

Use the screwdriver to connect the load (for example, a lamp) to the output of the transformer through electrical wires of suitable rating, depending on the load. Make sure that these wires are no longer than two meters (about 6-1/2 feet).

Double-check all the wiring. Turn on the circuit breaker.


In most places, working with electrical wiring requires an electrician's license. Check with your city clerk before doing any work on electrical wiring to see if you are allowed to perform that particular task. If you qualify, never let anyone, especially small children, stand near you while you are working with AC line wires, even if the circuit breaker is off.

Things You'll Need

  • Electronic transformer
  • Load-rated wires
  • Wire stripper
  • Screwdriver
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About the Author

Naeem Ahmed has been an established author of technical literature since 1989. He has numerous publications to his credit in peer-reviewed research journals such as "Physical Review Letters" and "Nuclear Instruments and Methods in Physics Research." With a Ph.D. in physics from Siegen University in Germany, he is an active researcher and academic.