LighTech LET-303 Electrical Transformer, 12V 300W Electronic Dimmable - Potted The dimmable LET 303 12Volts/300Watts LighTech electronic low voltage halogen lighting transformer can be dimmed by low cost TRIAC dimmers without producing any acoustic noise, which is a common problem for other electronic transformers The most compatible dimmers for these low voltage transformers are "trailing edge" or "reverse phase" wall dimmers which are commonly called electronic low voltage dimmers UL and cUL listed