OUTDOOR LIGHTING, TRANSFORMERS; You Can Keep Your Old Transformer - Any older low-voltage transformer can be used to power both halogen and LED lights—even if they're mixed on the same circuit—as long as you have enough wattage to spare in your old transformer. If your transformer isn't big enough to handle the additional load, add a second transformer or upsize your existing one.
Progress Lighting Landscape Lighting Transformer with Dusk-To-Dawn Sensor at Lowe's. Remote mount photo-cell that turns on transformer at dusk and off when ambient light appears. Includes 10 ft. of cord. To be used with plug-in compatible
Progress Lighting Multi-Tap Landscape Lighting Transformer at Lowe's. transformer w/plug-ins and easy wire terminal board for secondary connections and easy open enclosure with KO's for hardwiring and photocell