Automotive engineers were slow to adopt electronics applications because the cost was high compared to the benefits to consumers. Electrical systems were also very limited in the beginning. A starter on a 1912 model was the first electrical device used on an automobile. Electric headlights and horns followed quickly and replaced dangerous lanterns and bulb-type horns. By 1930, the six-volt electrical system was standard to most American automobile makes. The key electrical components at that time were the battery, the starter or cranking motor, the generator (also called a dynamo), the ignition system, the lighting system, and power for accessories and controls.

By the mid-1950s, 12-volt systems replaced the six-volt standard. After World War II, engine speeds and cylinder pressures increased, so the voltage demands for ignition were much greater. Manufacturers also provided a wider range of accessories such as multispeed windshield wipers, radios, and power windows...