How do I size a low voltage transformer?
VoltageDetermine the voltage your project requires. For alternating current (AC) applications, choose a transformer whose secondary rating is for the voltage you need. For direct current (DC) projects, select a transformer rated for 10 to 20 percent greater voltage than your project requires. Voltage regulators will use the excess to maintain a clean, steady voltage.CurrentSelect a transformer with a secondary current of about 20 to 50 percent more than your project needs. It’s better to overestimate current demand rather than underestimate it. An under-supply of current will make the circuits run poorly or not at all.SpaceDetermine the space you’ll need for a transformer, and buy the smallest one that fits your voltage and current needs. Generally, the more current a transformer provides, the larger the wires and iron core. Make sure there is unused space around the transformer to let cooling air flow around it.References:Enjoy the Music: “Choosing a Power Transformer;” Michael S.
