accident: an unplanned and unexpected event that can lead to injury to yourself and/or to others
alloy: a mixture of two or more metals
alternating current (AC): current that flows in one direction for a short period of time, then stops, and flows in the other direction
This process is repeated fot each cycle
ammeter: and instrument for measuring the amount of current flowing in a circuit
ampere: (amp or A) the unit used to measure current flow
An ampere of electricity is flowing when one coulomb of electricity flows past a point in 1 s. Ampere is often symbolized as I.
analog multimeter: see VOM
capacitor: a component that has the ability to store an electrical charge (electrons)
By storing an electrical charge, a capacitor can resist or oppose the changes in the voltage.
circuit: a pathway for electrons from a source, through conductors and components, and back to the source
circuit breakers: over-current components that trip to open the circuit and protect other electrical/electronic components from excess current flow; see fuses
Circuit breakers can be reset after they "trip" to continue protecting the circuit.
closed circuit: a complete pathway for electrons to go from the source, through the circuit, and back to the source
coaxial cable: cables designed for carrying radio-frequency current
complex circuit: a circuit that has components mounted so some are in series with other components and some are in parallel
conductors: materials that allow electrons travel freely through them
coulomb: the quantity of electricity created by a current of one ampere in one second, 6 240 000 000 000 000 000 electrons
crimp: bending metal tabs around wire and squeezing to make a connection between the wire and the terminal (end for the wire)
current: the rate of flow of electrons through a circuit
DC-power supply: a device that converts household alternating current (AC) into direct current (DC)
digital multimeter: see DMM
diodes: components that allow current to flow freely in only one direction
Diodes block the flow of current in the other direction.
direct current (DC): current that flows in one direction only--from a negative post, through a circuit, and back to a positive post
DMM: a digital multimeter; a multimeter that has a digital (numeric) readout for checking voltage, current flow, or resistance
DPDT switch: a double-pole, double-throw switch
This type of switch has two input terminals and two output terminals per pole.
DPST switch: a double-pole, single-throw switch
This switch has two input terminals and only one output terminal per pole.
electrical tape: a special plastic tape used to cover or insulate a joint
electromagnet: a strong temporary magnet made of a coiled wire (throgh which an electrical current is passed) around a metal core
electromotive force (emf): the electrical pressure that forces electrons through a circuit
The unit of emf is the volt (V).
equivalent resistance: the single resistance value that could be used to replace all of the resistors in parallel with each other
The following formula is used to find the equivalent resistance; !!!(insert formula hear)!!!
farads: the units of capacitance
If one coulomb of electricity, when stored in a capacitor, raises the voltage across the capacitor by one volt, then the capacotor has a capacity of one farad.
fibre-optic cable: a type of cable (with a transparent core) used to transmit data using pulses of light
flux: a material used to promote bonding of two metals
fuses: over current components that melt to open the circuit and protect other electrical/electronic components from excess current flow; see circuit breaker
Fuses must be removed and replaced after they "blow out."
grounded: connected to a common distribution or collection point for electrons
heat sink: a metal object clamped to the wires being soldered
Heat sinks carry the heat away and prevent component damage.
insulators: materials that resist the flow of electrons
joints: places where two or more wires are attached together; splices
jumper wires: lengths of wire used to connect one part of an electrical circuit to another
loads: devices that convert electrical energy into other forms of energy
multimeter: a device used to measure voltage, resistance, and current flow
normally closed switch: a switch that returns to the closed position when the actuator (level or switch) is released
normally open switch: a switch that returns to the open position when the actuator (level or plunger) is released
ohm: the unit used to measure the resistance or opposition to current flow
One ohm is the amount of resistance that would allow one ampere of current to flow when the emf is one volt.
Ohm's Law: the relationship of voltage, resistance, and current in a circuit
Ohm's Law is expressed by the formula V=IR.
open circuit: a circuit with a break or opening in it to stop the flow of electrons
parallel circuit: a circuit in which each component is connected to a separate branch
In a parallel circuit, the branches all have a common output.
patch cord: a cable that connects a sound-system component (phonograph, CD player, tape deck) to an amplifier, or VCRs to TVs (using video-in terminals)
perfboard: a Bakelite(tm) (a trademarked plastic) product used as an insulating material on which to mount components
polarity: the correct connection of positive and negative to the leads of a component
pole: the input terminal of a switch
prototype: the first actual product produced from a new design
A prototype is an experimental product used to see if the idea will work.
resistance: the opposition or resistance to the flow of electrons in a material
resistors: components used to reduce, oppose, or restrict current flow
schematic diagram: a map of the electrical/electronic circuit that shows the size and types of components used and how they are connected
series circuit: a circuit in which the compconents are connected one after the other with no branches
short circuit: an undesirable low-resistance path back to the current source
solder: an alloy of two metals--tin and lead
Solder is used to permanently attach electrical/electronic components.
solder bridge: a drop of solder that flows along the soldering iron on one side and along the wire on the other
A solder bridge conducts heat from the soldering iron to the point being soldered.
soldering: the formation of a metallic bond between two pieces of metal
splice: a place where two or more wires are attached together; see joints
SPDT switch: a single-pole, double-throw switch
An SPDT switch has one input terminal and one output terminal.
stranded: multi-strands twisted together
stripboard: flat, plastic material similar to perfboard but with copper strips that can be used as conductors
switch: a component used to stop and start the flow of current by opening and closing a circuit
throw: the output terminal of a switch
tinning: the process of adding a thin layer of solder to the tip of a soldering iron
transistors: semiconductor components that act as switches, variable resistors and amplifiers
unsafe act: any departure by a worker from an accepted, normal, or correct procedure or practice
unsafe condition: any hazardous physical circumstances, which if left uncorrected, may lead to an accident
volt: the unit of electrical or emf
Volt is symbolized by V.
voltage drop: the amount the voltage decreases across a component
VOM: an analog multimeter; and acronym for volt-ohm-milliameter
This style of multimeter has a pointer that sweeps across a dial. This style of multimeter is used for checking voltage, current flow, or resistance. It is superior for measuring voltage that varies because you can follow the needle movements of the analog meter (as opposed to the flickering reading on a digital multimeter).
wire wrap: a sloderless method of connecting wires to terminals