In the United States, power outlets are capable of distributing up to 120 volts to the devices to which they are attached. In order for that power to be used by an electronic device, it must be transformed to the appropriate voltage. A DC low voltage transformer uses a rectifier to convert its output to direct current (DC) and to lessen radio frequency interference (RFI). Low voltage transformers offer a variety of mounting configurations and are often small in size.
Transformers are a static piece of apparatus that transfers electrical energy from one circuit to another circuit by electro-magnetic induction, often with altered values of voltage and current. Electricity in a low voltage transformer is converted by passing a current from one set of electric windings to another by means of a magnetized core. Low voltage transformers are commonly used for low voltage lighting, which typically only uses 12 or 24 volts. There are also many low voltage transformers to meet the needs of defense, manufacturing, medical care and research industries.
Unlike high voltage transformers, which in the most extreme cases can weigh several hundred pounds, low voltage transformers can be small enough to hold between two fingers. There are two main ways that low voltage transformers are included in electronic device design. In the case of more expensive consumer electronics like video cameras and media players, low voltage transformers are usually built into external power cables and chargers. This reduces the likelihood that a voltage mismatch will affect the device in any way.
For example, if the owner of a video camera traveled to a country with a different standard outlet voltage and forgot to bring a step down transformer, the camera’s charger would likely be destroyed by excessive voltage, but it would prevent the excess of voltage from reaching the device itself, protecting it from damage. In other cases, voltage transformers can be designed as an integral part in a device. Devices with permanent power cords usually feature such integral transformers.