Electricity can have lower than normal voltage {brownout}|.
Incandescent bulb has wire {filament}| that resists electric current.
Metal strips {fuse}| that have low melting points melt if electric current gets too high. Short circuit or device that uses too much current {overload} causes high current.
If voltage becomes high enough, a spring {circuit breaker}| can open circuit.
Heaters {electric heat}| can use Nichrome wire to resist electric current flow and make heat.
Blankets {electric blanket}| can have thin insulated-wire networks. Wires are Nichrome.
Bread browners {toaster}| have Nichrome wire on sides, sometimes wound around thin mica sheets. Lowering toast starts electric current. Timer or thermostat holds toast down, until reaching time or temperature. Spring pops toast.
Nichrome heating elements have iron base and iron top, to toast both waffle sides {waffle iron}|.
Ovens {electric oven}| {oven, cooking} can have heating coils, or high-resistance conductors surrounded by insulators surrounded by metal, on bottom and at top {broiler, oven}. Electric-range burners use high-resistance conductor, surrounded by insulator, surrounded by metal, in a flat spiral.
drying, firing, or hardening oven {kiln}.
Irons {iron, steam} {steam iron}| can have a water tank with small holes. Water drips onto soleplate top to make steam, which comes out soleplate holes to wet and then dry clothes, so they appear smooth.
Irons have a heated flat bottom {soleplate}|.
Radar and microwave ovens have a vacuum tube {magnetron} in a magnetic field. Magnetic field rotates electron flow from hot cathode to anode. Rotation makes electron spokes that alternate on and off, at 2.45 gigahertz for microwave ovens, and resonate with an antenna that radiates microwaves.
Ovens {microwave oven}| can use very-high-frequency radio waves {radar wave}, from a magnetron, which heat food as water absorbs radiation. Radar waves reflect from metal, so oven stays cool. Paper and glass do not absorb radar waves much, so they stay cool. Food cooks evenly.
Variable resistors {memory resistor} {memristor}| can change electrical resistance when current changes (Leon Chua) [1971], so next time it has different resistance. For example, sending high current can set resistance high and sending low current can set resistance low. Later, moderate current encounters high or low resistance, like an ON-OFF switch and so like binary 1 or 0.
variable resistor {varistor}|.
Devices {switch, machine}| can turn current or voltage off or on.
types
Metal blade can slide into metal holder {knife switch}. Spring can make switch {snap action switch} stay in one position or the other. Snap switches can use a metal disc, which snaps from concave to convex. Half-filled tube of mercury liquid {mercury switch} can move from horizontal and closed to vertical and open. Switches can control one circuit {two-pole switch} or several circuits {multipole switch}.
circuit
Switches on stairs use a parallel circuit, and two different electrical paths can make switch be on.
safety
Perhaps, switches can be safe even when immersed. Such switches can be good in most appliances. Bakelite or other heat and current resistant, moldable material seals switch metal contacts. Wires to and from switch have watertight holders. Magnetism closes and opens switch, by moving throw inside Bakelite.
Switches can have locks to prevent young children from moving them.
Switches {relay}| can use a solenoid to open and close.
Switches {toggle switch}| can have levers.
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Date Modified: 2022.0225