To operate a 6 volt lamp from a 120 volt AC source with minimal waste power, which device is used?

To operate a 6 volt lamp from a 120 volt AC source with minimal waste power, the most effective device to use is a step down transformer. This device is specifically designed to reduce the voltage from a higher level (in this case, 120 volts) to a lower level (6 volts) while maintaining efficiency.

A step down transformer works on the principle of electromagnetic induction and transforms the voltage level while allowing current to flow through its coils. By efficiently converting the 120V AC input into a 6V AC output, it minimizes energy loss as heat, which is a common issue with other methods of voltage reduction such as resistors or linear voltage regulators.

Using a step down transformer is advantageous because it provides the required voltage for the lamp without excessive energy waste, offering a simple and efficient solution for the application. This makes it particularly suitable for powering low-voltage devices directly from a high-voltage source while preserving maximum energy efficiency.