LighTech LET-75-BF Electrical Transformer, 12V 75W Electronic Dimmable - Bottom Feed The dimmable LET-75-BF bottom feed 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