An input transducer, or a sensor, works by translating variations in an energy supply, like temperature or pressure, into an electrical signal. According to The Electronics Club, most input transducers convert energy into resistance, which is then turned into an electrical voltage by a voltage divider. A Light Dependent Resistor (LDR) is a transducer that uses light to generate electricity. According to Renewable Energy UK, light dependent resistors (also known as photoconductors) are a vital component within a variety of circuit boards, such as solar powered garden lights or night security lighting.
In "A Short Overview of Common Transducers," Kenneth Kuhn summarizes output transducers as producing a "real world signal" from an electrical input, meaning that they convert voltage into another quantity. Output transducers are incorporated into a range of devices that we use within our daily life. Lamps, for example, use output transducers to convert electricity into light. According to The Electronics Club, most electronic circuits use both output and input transducers.
Because there is no standardized supply of electricity, converters bridge the gap between the varying voltage signals and frequencies (cycles per second). Most devices, for example, are installed with internal converters, allowing them to adapt from AC voltage to DC voltage (and vice versa). The most common converter is a mains converter. Mains converters enable devices to adapt to the voltage of a particular geographical region to be used within another, such as the travel adapter you use when on holiday in Europe. Mains converters also resolve the variations in plugs and electrical outlets across regions.