Ammeter through a wire which expands as it heats. Although these instruments have slow response time and low accuracy, they were sometimes used in measuring radio-frequency current. These also measure true RMS for an applied AC. In much the same way as the analogue ammeter formed the basis for a wide variety of derived meters, including voltmeters, the basic mechanism for a digital meter is a digital voltmeter mechanism, and other types of meter are built around this. Digital ammeter designs use a shunt resistor to produce a calibrated voltage proportional to the current flowing. This voltage is then measured by
Main Street Electrical Parade Street Electrical Parade was the Electrical Water Pageant, a show made up of fourteen 25-foot-tall (7.6 m) screens with electrical lights placed on them. Not long after the Electrical Water Pageant debuted, Card Walker commissioned the development of what became the Main Street Electrical Parade to provide Disneyland with a similar nighttime visual spectacle. The parade's design used nickel–cadmium batteries, which the Disney movie studio had recently started using, and Italian-made miniature bulbs that Disneyland staff had seen in light displays along Michigan Avenue in Chicago, Illinois. Disney arranged for the parade's original floats to be constructed by Silvestri, the