A transducer is a device that converts one form of energy into another. It takes a non-electrical input signal, such as temperature, sound, or light, and converts it into an electrical output signal, such as voltage, current, or capacitance. Transducers have sensing elements that detect physical quantities and transduction elements that convert the non-electrical signal into an electrical one. Examples of transducers include microphones, light bulbs, and electric motors. Key characteristics for transducers include accuracy, linearity, repeatability, stability, sensitivity, size, dynamic range, error, speed, noise, hysteresis, and ruggedness.