plugs

[madibug131]

what are isolating transformers  when should they be used

[Jay70]

Hi madibug131,

An isolating transformer is used when one circuit is required to supply the same level of voltage and current to another but electrical isolation between the two is needed.  The voltage is transfered in any transformer via the electromagnetic field propergation in the primary winding which induces a voltage in the secondary winding of a magnitude proportinal to the devices turns ratio but without being conected to it via a direct wire link.  All transformers isolate the input from the output but the important factor about an isolating transformer is it's turns ratio which is 1: 1 so the output voltage and current is the same as the input voltage excluding any small losses.

Hope this helps

[Eddiecurrent]

An isolating transformer is designed so that there is no direct connection to the secondary side when looking into the primary side. Usually they have a ratio of 1:1 (as has been stated) there may or may not be an earth but the fact that the secondary is completely separate to the mains provides that isolation. You can still get a shock if you happen to form part of the phase to neutral circuit. Only transformers that have two separate windings (and are adequately insulated) can be regarded as isolating. Auto transformers however are designed using only one winding so they have a direct connection to mains potential and earth. These should never be considered as isolating.Isolating transformers can be used where there is a possibilty of a person coming into contact with mains potentials (such as the live tesing of power supplies and so forth) whilst connected to or in contact with the earth. This case is considering a mains transformer but in practice there are others that will perform isolation of circuits within electronic equipment etc.