two examples where low voltage transformers are used
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title: Low-voltage network text: significantly varies depending on configuration. They are sited on pole tops, cellars or designated small plots. From these transformers, "low-voltage" or "secondary" network branches off to the customer connections at customer premises, equipped with electricity meters. Most of differences in the layout and design of low-voltage networks are dictated by the mains voltage rating. In Europe and most of the world 220–240 V is the dominant choice, while in North America 120 V is the standard. ANSI standard C84.1 recommends a +5%, −2.5% tolerance for the voltage range at a service point. North American LV networks feature much shorter secondary title: Transformer types text: or between a high impedance instrument output and the low impedance input of a mixing console. Audio transformers that operate with loudspeaker voltages and current are larger than those that operate at microphone or line level, which carry much less power. Bridge transformers connect 2-wire and 4-wire communication circuits. Being magnetic devices, audio transformers are susceptible to external magnetic fields such as those generated by AC current-carrying conductors. "Hum" is a term commonly used to describe unwanted signals originating from the "mains" power supply (typically 50 or 60 Hz). Audio transformers used for low-level signals, such as those from microphones, title: Low-voltage network text: connections, up to , while in European design they can reach up to . North American distribution transformers must be therefore placed much closer to consumers, and are smaller (25–50 kVA), while European ones can cover larger areas and thus have higher ratings (300–1000 kVA); only the remote rural areas in European design are served by single-phase transformers. As the low-voltage distribute the electric power to the widest class of end users, another main design concern is safety of consumers who use the electric appliances and their protection against electric shocks. An earthing system, in combination with protective devices such title: Low-voltage network text: the "medium-voltage" or "primary" network, operated at a medium voltage level, typically 5–35 kV. Feeders range in length from a few kilometers to several tens of kilometers. As they must supply all customers in the designated distribution area, they often curve and branch along the assigned corridors. A substation typically supplies 3–30 feeders. Distribution transformers or "secondary transformers", placed along feeders, convert the voltage from the medium to a low voltage level, suitable for direct consumption by end customers (mains voltage). Typically, a rural primary feeder supplies up to 50 distribution transformers, spread over a wide region, but the figure title: Transformer types text: Transformer types A variety of types of electrical transformer are made for different purposes. Despite their design differences, the various types employ the same basic principle as discovered in 1831 by Michael Faraday, and share several key functional parts. This is the most common type of transformer, widely used in electric power transmission and appliances to convert mains voltage to low voltage to power electronic devices. They are available in power ratings ranging from mW to MW. The insulated laminations minimizes eddy current losses in the iron core. Small appliance and electronic transformers may use a split bobbin, giving a