what is isolation through transformers?

Hi,

All this means is that there is a transformer in the power circuit that isolates you from the "mains", ""line voltage", essentially the current source that you plug the radio, or other device into for power.

This allows a greater degree of saftey because it can limit the amount of current you may accidently come into contact while servicing hte radio. There are some other factors too regarding current.

Second and more importantly, if there should be faulty wiring in the radio, or in the house wiring that can lead to a shock hazard by just touching the chassis, isolating the radio with a transformer reduces that danger if you happen to have been in contact with "Earth ground". In a sense, the same reason birds can safely perch on power lines. There is not a complete path for current to flow.

: what is isolation through transformers?

Hi Sunnish, The electrical authorities earth one side (Neutral wire) of the mains in their system. The other wire (Active) has the full mains voltage referenced to ground as a result and if you touch between Active and ground there's a severe shock hazard. The ground makes a good return conductor. To reduce this danger an Isolation transformer is used. The mains transformer fitted in equipment performs this function but where live chassis (transformerless construction) is used an external transformer is used. These are what are usually refered to as Isolation Transformers and have a 1:1 ratio so the secondary voltage is the same as the mains but the winding isn't earthed, it's left floating. So now if one wire is touched there's no return path via ground and no shock hazard. If you get across the supply, between the two mains wires then you'll still get a shock. Isolation transformers usually have a normal mains socket wired to the output so the radio or whatever you're working on can be plugged in to operate it safely. The transformer must be large enough to supply the full current drawn by the appliance. Don Black.

: what is isolation through transformers?