tx's ID for electronic or toroidal?

[--tom]

How do i tell if in-situ tx's for down lights are toroidal or electronic?

 

[aptsys]

Can you gain access to the transformers? If you can, electronic transformers are very lightweight and usually of a shape/size not possible for EI or Toroidal transformers.

If you cannot gain access, a multimeter set to measure resistance will give you a clue. Electronic transformers will usually give a rising resistance as the capacitors charge after the rectifier, whereas toroidal transformers will give a constant resistance. Make sure you are only testing the transformer and nothing else. Turn off all power too!

You may also hear a characteristic hum, especially at turn on, with toroidal transformers.

Another test would be to remove all lamps and test the voltage at the lamp holder. Electronic transformers usually disable the output with no lamp inserted, whereas toroidal transformers will give you a slightly higher than normal reading (14 or 15VAC). If you have a frequency measurement setting on your multimeter, expect 50Hz for toroidal and >25kHz for electronic.

A destructive test would be to do a 500V or 1000V insulation test. Electronic transformers won't work afterwards

 

[--tom]

aptsys, thanks for that detailed info.
T.