I'm not sure about "Low Voltage" dimmers, but I believe the scr-type controller in the dimmer for electronic LV transformers operates in reverse than the typical scr...
Instead of the current being let through at a certain point on the voltage wave (the trigger point) which would cause a bit of a surge, the current comes on at zero and shuts off at a corresponding trigger point. From what I understand, this protects electronic LV dimmers from spikes while allowing the same average, (or RMS?) current flow through the electronics.
Standard dimmers can be used on most magnetic LV transformers.
[This message has been edited by Redsy (edited 10-06-2005).]