Some transformers cannot be dimmed
Some transformers cannot be dimmed unless they have a compatible dimmer.
Some dimmers are not suitable for dimming anything other than a straight GLS tungsten lamp.
Dimmers also flicker/fail if they have too much or too little load
Each dimmer has its own requirements. typical compatibility guide here http://www.tlc-direct.co.uk/Technical/DataSheets/Systems/Dimmer_Selector_June_2011_A.pdf
Some transformers cannot be dimmed unless they have a compatible dimmer.
Some dimmers are not suitable for dimming anything other than a straight GLS tungsten lamp.
Dimmers also flicker/fail if they have too much or too little load
Each dimmer has its own requirements. typical compatibility guide here http://www.tlc-direct.co.uk/Technical/DataSheets/Systems/Dimmer_Selector_June_2011_A.pdf