R: The symbol for resistance.RC (resistance/capacitance) time constant: A formula to calculate the time
required to charge a capacitor to two-thirds or discharge it to one-third of its
capacity.relay: A device that performs like a switch. It closes or opens a circuit,
depending on the voltage that you supply.resistance: The measurement of the ability of electrons to move through any
material.resistor: A component of a circuit that reduces the amount of electrons that
flow through the circuit.rosin flux remover: An after-soldering cleaner that removes any remaining
flux so that it doesn’t oxidize your circuit.schematic: A drawing that shows how components in a circuit are connected.semiconductor: A material, such as silicon, that has some of the properties
of both conductors and insulators.semiconductor temperature sensors: A type of sensor that measures temper-
ature electrically.sensors: Electronic components that sense a particular condition, such as
heat or light.series circuit: A circuit in which current runs through each component in
sequence.short circuit: What happens when two wires are connected and current goes
through them, resulting in the circuit not being completed.sine wave:An signal that switches from a high voltage to a low voltage, back
to the high voltage, and then repeats this cycle with a smooth sinesoidal
(curvy) waveform until it’s shut off.single-pole, double-throw switch (SPDT):A type of switch in which one wire
goes into the switch and two wires leave the switch.single-pole switches: A type of switch with one input wire.slide switch:A switch that you slide forward or backward to turn an elec-
tronic device on or off.Glossary 387
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