A Lighting Transformer is a device that increases or decreases voltage and current to lighting fixtures. The most important thing to remember about lighting transformers is if you exceed 90% of a transformers load capacity its life will decrease and the fixtures may not light properly.
Lighting transformers are widely used in many applications as landscape lighting, low voltage indoor lighting, track lighting, cable lighting and more.
The use of a lighting transformers is most common for reducing the voltage from 120V to 12V or 24V. Many lighting fixtures operate on low voltage current and need either a remote transformer or a built in transformer. There are mainly two types of lighting transformers, low voltage magnetic transformers and low voltage electronic transformers.
Common transformers and their capacities are 300W, 600W, 1000W, and 1200W. You want to know capacity of the lighting transformer you need for your application. For example when setting up outdoor lighting you want to calculate the wattage that is going to be used for the lights. You can do this by simply using the following formula: Number of fixtures X watts per bulb.
Example: If you were to set up 10 fixtures that are 20W per bulb (12 x 20 = 240), a 300W transformer is ideal for this set up. Remember to take in consideration the voltage drop on the wires which is ten time larger than when having a regular 120V system.