Hello all, for the protection of a telephone exchange, from voltage transient, spikes etc, which is more useful and applicable, an Isolation transformer or a constant voltage transformer (C.V.T.) ?

I beleive the Constant Voltage Transformer is better than isolation transformer as in constant voltage transformer protect the device from any spikes,high volatage low poer factor etc.

Isolation transformer particullary use to decouple the the two circuits and only fed AC input as it as to secondory.