Digital Electronics Unit 1

Key terms and color coding practice.
An electrical device used to store electrical charge.
Cold Solder Joint
A solder connection that exhibits poor wetting and is characterized by a grayish, porous appearance due to excessive impurities in the solder, inadequate cleaning prior to soldering and/or the insufficient application of heat during the soldering process.
Digital Multimeter
Electronic test equipment that can perform multiple tasks. Typically one capable of measuring voltage, current, and resistance. May also measure capacitance, inductance, current gain of transistors, and/or anything else that can be measured electronically.
A two terminal device that conducts in only one direction.
Dual In-Line Package
A very common IC package with two parallel rows of pins intended to be inserted into a socket of through holes drilled in a printed circuit board.
Engineering Notation
A floating point systerm in which numbers are expressed as products consisting of a number greater than one multiplied by an appropriate power of ten that is some multiple of three.
A protective device in the current path that melts or breaks when current exceeds a predetermined maximum value.
Light-emitting diode. An electronic device that conducts current in one direction only and illuminates when it is conducting.
Plastic Leaded Chip Carrier (PLCC)
A square IC package with leads on all four sides designed for surface mounting on a circuit board.
Printed Circuit Board
Insulating board containing conductive tracks for circuit connections.
Component made of material that opposes flow of current and therefor has some value of resistance.
Resistor Color Code
Coding system of colored stripes on a resistor to indicate the resistor's value and tolerance.
Scientific Notation
Numbers entered a s a number from one to ten multiplied by a power of ten.
SI Notation
Abbreviation of System International, a system of practical units based on the meter, kilogram, second, ampere, Kelvin, mole and candela.
Seven-Segment Display
An array of seven independently controlled light-emitting diodes (LED) or liquid crystal display (LCD) elements, shaped like a figure-8, which can be used to display decimal digits and other character by turning on the appropriate elements.
Small Outline IC (SOIC)
An IC package similar to a DIP, but smaller, which is designed for automatic placement and soldering on the surface of a circuit board.
Metallic alloy of tin and lead that is used to join two metal surfaces.
Solder Bridge
The unwanted formation of a conductive path of solder between conductors.
Process of joining two metallic surfaces to make an electrical contact by melting solder (usually tin and lead) across them.
Soldering Iron
Tool with an internal heating element used to heat surfaces being soldered to the point where the solder becomes molten.
The process of applying a thin coat of solder to materials prior to their being soldered; for example, application of a light coat of solder tot he filaments of a conductor to hold the filaments in place prior to soldering the conductor.
Term derived from "transfer resistor." Semiconductor device that can be used as an amplifier or as an electronic switch.
A way of representing some physical quantity, such as temperature of velocity, by a proportional continuous voltage or current. An analog voltage or current can have any value within a defined range.
The instantaneous voltage of a waveform. Often used to mean maximum amplitude, or peak voltage, or a pulse.
The smallest particle of an element that still has the same characteristics as the element.
A circuit board for wiring temporary circuit, usually used for prototypes or laboratory work.
Any material that allows the free movement of electric changes, such as electrons, to provide an electric current.
Conventional Current
The direction of current flow associated with positive charge in motion. The current flow direction is from a positive to negative potential, which is in the opposite direction of electron flow.
Digital signal in the form of a rectangular pulse train or a square wave.
A movement of electrical charges around a closed path or circuit.
A way of representing a physical quantity by a series of binary numbers. A digital representation can have only specific discrete values.
Digital Waveform
A series of logic 1s and 0s plotted as a function of time.
Digital Multimeter (DMM)
A piece of test equipment used to measure voltage, current, and resistance in an electronic circuit.
Duty Cycle (DC)
Fraction of the total period that a digital waveform is in the HIGH state.
Basic particle of negative charge in orbit; around the nucleus in an atom.
Electron Flow
Current of negative charges in motion. Direction is from the negative terminal of the voltage source, through the external, circuit, and returning to the positive side of the source. Opposite to the direction of conventional current.
Falling Edge
The part of a pulse where the logic level is in transition from a HIGH to a LOW.
The number of cycle per unit time of a periodic waveform.
Hertz (Hz)
Unit of frequency. One hertz equals one cycle per second.
A material that does not allow current to flow when voltage is applied because of its high resistance.
Kirchhoff's Current Law (KCL)
The algebraic sum of all currents into and out of any branch point in a circuit must equal zero.
Kirchhoff's Voltage Law (KVL)
The algebraic sum of all voltages around any closed path must equal zero.
Logic HIGH
The higher of two voltages in a digital system with two logic levels.
Logic LOW
The lower of two voltages in a digital system with two logic levels.
The massive, stable part of the atom that contains both protons and neutrons.
Unit of resistance. Value of one ohm allow current of one ampere with potential difference of one volt.
Ohm's Law
In electric circuits, I=V/R
A piece of test equipment used to view and measure a variety of different wave forms.
Parallel Circuit
One that has two or more branches for separate current from one voltage source.
The amount of time required for one complete cycle of a periodic event of waveform.
Particle with positive charge in the nucleus of an atom.
Testing design function by specifying a set of inputs and observing the resultant outputs. It is generally shown as a series of input and output wave forms.
Opposition to current. Unit is the ohm.
Series Circuit
One that has only one path current.
Sine Wave
One in which amplitude varies in proportion to the sine function of an angle.
Square Wave
An almost instantaneous rise and decay of voltage or current in a periodic pattern with time and with a constant peak value.
555 Time
TTL-compatible IC that can be wired to operate in several different modes, such as a one-shot and an astable.