switch wiki:
>This article is about electrical switches. For other meanings of the word "switch", see Switch (disambiguation). A switch is a device for making or breaking an electric circuit, or for selecting between multiple circuits. In the simplest case, a switch has two pieces of metal called contacts that touch to make a circuit, and separate to break the circuit. The contact material is chosen for its resistance to corrosion, because most metals form insulating oxides that would prevent the switch from working. Sometimes the contacts are plated with noble metals. They may be designed to wipe against each other to clean off any contamination. Nonmetallic conductors, such as conductive plastic, are sometimes used. The moving part that applies the operating force to the contacts is called the actuator, and may be a toggle or dolly, a rocker, a push-button or any type of mechanical linkage (see photo).
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Flat wiki:
ternate uses: Flat (disambiguation)In music, flat means "lower in pitch." More specifically, in music notation, flat means "lower in pitch by a semitone," and has an associated symbol (), which looks like a lowercase "b"; the note A flat is shown in musical notation in Figure 1. Under equal temperament, C flat is the same as, or enharmonically equivalent to, B and F flat is the same as E. There also exist double-flats, which look like and lower a note by two semitones. Less often one will encounter half, three-quarter, or otherwise altered flats.
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