Insulators protect equipment and life from electric shock. Inverter — An apparatus that converts direct current into alternating current. Kilowatt-hour kWh — The product of power in kW and time in hours. Equal to Watt-hours. For example, if a W light bulb is used for 4 hours, 0. Electrical energy is sold in units of kWh. Kilowatt-hour Meter — A device used to measure electrical energy use. Kilowatt kW — Equal to watts. Load — Anything which consumes electrical energy, such as lights, transformers, heaters and electric motors.
Mutual Induction — Occurs when changing current in one coil induces voltage in a second coil. One ohm is equivilant to the resistance in a circuit transmitting a current of one ampere when subjected to a potential difference of one volt. Ohmmeter — An instrument for measuring the resistance in ohms of an electrical circuit. Open Circuit — An open or open circuit occurs when a circuit is broken, such as by a broken wire or open switch, interrupting the flow of current through the circuit.
It is analogous to a closed valve in a water system. Parallel Circuit — A circuit in which there are multiple paths for electricity to flow. Each load connected in a separate path receives the full circuit voltage, and the total circuit current is equal to the sum of the individual branch currents.
Piezoelectricity — Electric polarization in a substance especially certain crystals resulting from the application of mechanical stress pressure. Power — The rate at which electrical energy is transferred by an electric circuit. Measured in Watts. Power Factor — The ratio of the actual electrical power dissipated by an AC circuit to the product of the r. The difference between the two is caused by reactance in the circuit and represents power that does no useful work.
Protective Relay — A relay device designed to trip a circuit breaker when a fault is detected. Reactive Power — The portion of electricity that establishes and sustains the electric and magnetic fields of AC equipment. Exists in an AC circuit when the current and voltage are not in phase.
Measured in VARS. Rectifier — An electrical device that converts an alternating current into a direct one by allowing a current to flow through it in one direction only. Relay — An electrical coil switch that uses a small current to control a much larger current.
Reluctance — The resistance that a magnetic circuit offers to lines of force in a magnetic field. Resistance — The opposition to the passage of an electric current. Electrical resistance can be compared to the friction experienced by water when flowing through a pipe. Measured in ohms. Resistor — A device usually made of wire or carbon which presents a resistance to current flow.
Rotor — The rotating part of an electrical machine such as a generator, motor, or alternator. Self Induction — Voltage which occurs in a coil when there is a change of current. Semiconductor — A solid substance that has a conductivity between that of an insulator and that of most metals, either due to the addition of an impurity or because of temperature effects.
Devices made of semiconductors, notably silicon, are essential components of most electronic circuits. Series-Parallel Circuit — A circuit in which some of the circuit components are connected in series and others are connected in parallel. Capacitance or capacitor. A capacitor is a passive electronic component with two leads or legs or terminals that stores electrical energy in an electric field. Computer aided design. The process of creating a technical drawing with the use of computer software.
Computer aided manufacturing. Using computer software and computer-controlled machinery to automate a manufacturing process. Common base configuration. Configuration where the base terminal of a transistor is a common to both the input and output signals. Common collector. Configuration where the collector terminal of a transistor is a common to both the input and output signals. Common emitter. Configuration where the Emitter terminal of a transistor is a common to both the input and output signals.
Central processing unit. The main IC of a computer, tablet, smartphone or high-end electronic gadgets, that does all the main data processing work. The SI unit of electric charge. Junction diode. A semiconductor diode in which a PN-junction is formed by fusing N-type material with a P-type material for doing rectification work. All solar cells are junction diodes. Cathode ray Oscilloscope. An electronic test instrument to obtain waveform of different input signals. Also called Oscillograph.
Cathode ray tube. A high-vacuum tube that produces cathode rays phosphorescent screen, and is used to display images on TV or Computer Screen. Deci 10 A decimal unit prefix in the metric system denoting a factor of one tenth. Digital to Analog. In electronics, a digital-to-analog converter converts a digital signal into an analog signal. Dual in-line package. A rectangular electronic component with parallel pins on both sides. These packages can be soldered directly to the PCB or inserted in a socket.
Digital Multimeter. A test and measurement tool with a digital display to measure electrical values like voltage volts , current amps and resistance ohms. Digital voltmeter. An instrument used to measure electrical potential difference between two points in an electric circuit.
Difference in potential. The amount of work done in carrying a unit charge from one point to another in an electric field. A test to check functioning of heart by measuring the electrical activity of the heart in the form of impulse or wave. Extremely high frequency. Radio frequencies in the electromagnetic spectrum from 30 to gigahertz GHz.
Electromagnetic interference. Disturbance caused by an external source that affects an electrical circuit by electromagnetic induction, electrostatic coupling, or conduction.
Field effect transistor. An electronic component that uses an electric field to control the flow of current. A conducting wire with a high melting point used in an electric bulb or thermionic valve. Frequency modulation. Encoding of information in a carrier wave by varying the instantaneous frequency of the wave.
Frequency at resonance. The tendency of a system to oscillate at maximum amplitude at certain frequencies. A digital modulation technique in which the frequency of the carrier signal varies according to the digital signal changes.
Full scale deflection. The full range of motion of an analog needle of an analog meter, or a galvanometer. SI unit of electrical inductance. Access Bus. Is a low speed 4-wire serial bus once used on Personal Computers.
The Access bus has a maximum speed is kbps over a maximum cable distance of 10 meters, however a repeater may be used. Refer to the following page for a description of the Access Bus interface page. An assembly of a group of parts or a unit which is not always required for the operation of a set or unit as originally designed but serves to extend the functions or capabilities of the set, such as headphones for a radio set supplied with a loudspeaker, a separate power unit for use with a set having a built-in power supply, or a remote control unit for use with a set having integral controls.
Access Time. The difference in time between when data is requested and when data is delivered. The time lapsed between a given command and when the function is performed.
The time for the [disk drive] access arm to reach the desired track and the delay for the rotation of the disk to bring the required sector under the read-write mechanism. AC Coupling. The interconnection between two circuits through a capacitor, transformer or other device which passes AC voltage but blocks any DC component.
C3 in the circuit to the right is a DC blocking capacitor. AC Coupled Amplifier. This circuit style is also called RC coupling, with the resistors also affecting the signal between stages. Same as DC Blocking. A register that both stores a number and adds to other numbers loaded into the register. AC generator. Acknowledge Character. AC Line Voltage.
See Line voltage. Acorn Tube. A small tube, used in low power uhf circuits, with closely spaced electrodes and no base. The tube is connected to its circuits by short wire pins that are sealed in a glass or ceramic envelope. Impedance — The measure of the opposition that a circuit presents to a current when a voltage is applied.
Impedance extends the concept of resistance to AC circuits, and possesses both magnitude and phase, unlike resistance, which has only magnitude. Inductance — The property of a conductor by which a change in current flowing through it induces creates a voltage electromotive force in both the conductor itself self-inductance and in any nearby conductors mutual inductance. Measured in henry H. Inductor — A coil of wire wrapped around an iron core.
The inductance is directly proportional to the number of turns in the coil. Insulator — Any material where electric current does not flow freely. Insulative materials, such as glass, rubber, air, and many plastics have a relatively high resistance. Insulators protect equipment and life from electric shock.
Inverter — An apparatus that converts direct current into alternating current. Kilowatt-hour kWh — The product of power in kW and time in hours. Equal to Watt-hours. For example, if a W light bulb is used for 4 hours, 0. Electrical energy is sold in units of kWh. Load — Anything which consumes electrical energy, such as lights, transformers, heaters and electric motors. Load Rejection — The condition in which there is a sudden load loss in the system which causes the generating equipment to be over-frequency.
A load rejection test confirms that the system can withstand a sudden loss of load and return to normal operating conditions using its governor. Load banks are normally used for these tests as part of the commissioning process for electrical power systems.
Mutual Induction — Occurs when changing current in one coil induces voltage in a second coil. One ohm is equivilant to the resistance in a circuit transmitting a current of one ampere when subjected to a potential difference of one volt.
Ohmmeter — An instrument for measuring the resistance in ohms of an electrical circuit. Open Circuit — An open or open circuit occurs when a circuit is broken, such as by a broken wire or open switch, interrupting the flow of current through the circuit.
It is analogous to a closed valve in a water system. Parallel Circuit — A circuit in which there are multiple paths for electricity to flow. Each load connected in a separate path receives the full circuit voltage, and the total circuit current is equal to the sum of the individual branch currents. Piezoelectricity — Electric polarization in a substance especially certain crystals resulting from the application of mechanical stress pressure.
Power — The rate at which electrical energy is transferred by an electric circuit. Measured in Watts. Power Factor — The ratio of the actual electrical power dissipated by an AC circuit to the product of the r. The difference between the two is caused by reactance in the circuit and represents power that does no useful work. Protective Relay — A relay device designed to trip a circuit breaker when a fault is detected. Reactive Power — The portion of electricity that establishes and sustains the electric and magnetic fields of AC equipment.
Exists in an AC circuit when the current and voltage are not in phase. Measured in VARS. Rectifier — An electrical device that converts an alternating current into a direct one by allowing a current to flow through it in one direction only. Relay — An electrical coil switch that uses a small current to control a much larger current.
Reluctance — The resistance that a magnetic circuit offers to lines of force in a magnetic field. Resistance — The opposition to the passage of an electric current. Electrical resistance can be compared to the friction experienced by water when flowing through a pipe. Measured in ohms.
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