An isolation transformer is an ordinary transformer with primary and secondary windings. It usually has an equal number of turns on both windings so the input-output voltages are equal. Such transformers are commonly used on the AC mains to isolate (with very high resistance) an instrument from the power source.
Another kind of isolation transformer is audio isolation transformer. It is 1:1 in most cases. Using isolation transformer enables the secondary circuit to be galvanically isolated from the primary circuit. Actually any kind of transformer does this.
isolation transformer usually has an equal number of turns on both windings so the input-output voltages are equal. Such transformers are commonly used on the AC mains to isolate the actual ckt
from the power source.
electronicman,
Some isolation transformers hava a "Faraday shield", which is just a metal foil that is inserted between the primary and secondary. This shield, which must be grounded, greatly reduces the capacitive coupling between the primary and secondary.
Regards,
Kral