terminal: A piece of metal to which you hook up wires (for example, a bat-
tery terminal).thermistor: A resistor that changes its resistance value when the tempera-
ture changes.thermocouple: A sensor that measures temperature electrically.tinning: The process of heating a soldering tool to full temperature and apply-
ing a small amount of solder to the tip. This prevents solder from sticking to
the tip.tolerance: The variation in the value of a component due to the manufactur-
ing process that is allowable, typically expressed as a range.traces: On a circuit board, the wires that run between pads to electrically
connect components.transistor: A semiconductor that controls the flow of electric current.V:The symbol for voltage. Also can represented by E.variable capacitor: A capacitor that includes two or more metal plates that
are separated by air. If you turn the knob, you change the capacitance of a
device. See alsocapacitor.variable coil: A coil of wire that surrounds a movable metal slug. When you
turn the slug, you change or vary the inductance of the coil.variable resistor: Seepotentiometer.voltage: Attractive force between positive and negative charges.voltage divider:The voltage drops in a circuit that produce voltage lower
than the supply voltage at certain points in the circuit.voltage drop: The lowering of voltage that occurs when voltage pulls elec-
trons through resistors (or any other component) and the component uses
up a portion of the voltage.voltage spike: A brief increase in voltage.watt hour: A unit of measure for energy; the ability of a device or circuit to
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