Russell Baron
Hi Peter If your changing from halogen to LED it will be a driver you need not a transformer. Your transformer may be say 60-100w but if you replace your lamps with LED the wattage will be less than the 60w so wont work properly,they may pulse on and off. Therefore you will need to replace the 12v transformer with a LED driver.Work out how many LED lamps you have on the circuit in watts and get a driver that exceeds that wattage. Hope this makes sense Thanks Russ