If you cannot find the transformer that came with this set of lights, might I suggest that you contact your local electronics supplier (Maplin can help here) and explain the situation. They may be able to sell you the parts to make it work again. You will need a transformer, switchable to 6v (try this one first), 9v (then this one) or 12V (finally this one) and something to connect to the lights. I would NOT recommend twisting the wires together by hand and using insulating tape. This could be a fire risk. You may be able to buy a special plug that comes in two halves that you can connect to the transformer and the lights.