Technical Engineering Dictionary
"A" "B" "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M",
"N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"

'Ha' to 'Hd', 'He', 'Hf' to 'Hor', 'Hor' to 'Hz',

Half Adder. A circuit that adds two 1-bit binary numbers and output a sum bit and a carry bit, but does not have a provision to accept a carry input from a previous adder stage. Two Half Adders can be combined to form a Full Adder.

Half Adder Logic Schematic using AND, NAND and NOR gates
Half Adder

Half-Duplex. [HDX] Data flow in either direction, but not in both directions at the same time. There are a number of interface buses that only allow Half-Duplex operation, while some bus networks just add a redundant path in the opposite direction to allow communication in either direction at the same time. Operation in both directions at the same time is called Full-Duplex. An Abbreviation for half duplex is HDX.

Half-Power Point. A point on a waveform or radar beam that corresponds to half the power of the maximum power point.

Half-wave Dipole. A style of Dipole Antenna [more details located in the dictionary of Antenna terms].

Half-Wave Rectifier. A rectifier using only one-half of each cycle to change ac to pulsating dc. The direction of the diode or the winding of the transformer selects the polarity of the output across the load. Resistor Rs is not required but is used to limit the current through the diode. Refer to the Half-Wave Rectifier Circuit detail.

Half wave diode rectifier circuit
Half Wave

Half-Wave Voltage Doubler. Two half-wave voltage rectifier circuits connected to double the input voltage. Read more on Voltage Multiplier Circuits. A voltage doubler circuit that only operates on half of the input cycle.

Hall Effect. An electric field that is produced when a current carrying conductor is placed in a magnetic field whose direction is perpendicular to both the direction of the current and the magnetic field.

Hall Effect Device. A Hall Effect Sensor component or device.

Halt. A command that stops the transfer of data on a bus, or stops the executions of commands by a processor.

Hamming Code. An error-detecting and error-correcting binary code, used in data transmission, that can detect all single- and double-bit errors and correct all single-bit errors.

Hamming Weight. The number of non-zero symbols in a symbol sequence.

Hand-Shake. The interchange of signals between a 'talker' and a 'listener' to exchange data on a bus. During a Handshake a listener [slave] indicates ready for data, a talker [master] indicates data ready, the slave then indicates data received. Read more on the Handshaking Protocol. Handshaking is normally used when interfacing to peripherals that communicate at different speeds, or transfer data at different rates. Handshaking allows the devices to communicate at the same rate, as determined by the speed of the mutual handshake.

Handshacking. How one device communicates with one or more other devices, at a predetermined speed. However the actual speed of the transfer could vary for every different transfer, because the transfer speed is defined as when both devices are ready. See Handshaking Protocol.

Hard Copy. A physical print out.

Hard Disk. [HD] A flat, circular, rigid plate with a magnetizable surface on one or both sides used to store data. Also called a Hard Disk Drive [HDD]. Note: A hard disk is distinguished from a diskette [floppy Disk] by virtue of the fact that it is rigid and not considered removable. Manufacturers of Hard Disk Drives.

Open Case HDD Platter and Drive Arm
Hard Disk Drive

Hard Disk Controller. The section of the hard disk that receives commands from a processor and than performs disk transfers.

Hard Disk Drive. [HDD] See Hard Disk.

Hard Drive. [HD] See Hard Disk.

Hard-Tube. A high-vacuum electron tube modulator that uses a driver for pulse forming. See Vacuum Tube.

Hardware. The physical equipment or component used to perform some function, in contrast to software.

Hardware Interrupt. An interrupt signal received from a component external to the processor operating on the interrupt. A signal to the processor that a peripheral requires attention.

Harmonic. A frequency that is a whole-number multiple of a smaller base frequency. Of a sinusoidal wave, an integral multiple of the frequency of the wave. Harmonic percentages of a half sine wave; 2nd, 21.2%, 3rd, 0%, 4th 4.2%, 5th, 0% and 6th harmonic is 1.8%.

Harmonic Distortion. A ratio of 100 times the sum of all the harmonics to the fundamental. In the output signal of a device, distortion caused by the presence of frequencies that are not present in the input signal, caused by nonlinearities within the device. The production of harmonic frequencies at the output of a nonlinear device when a sinusoidal signal is applied to the input.

Harness. An assembly of wires or cables, or wires and cables arranged so it may be installed or removed as a unit in the same electronic or electrical equipment. One or more insulated wires or cables, with or without helical twist; with or without common covering, jacket, or braid; with or without breakouts; assembled with two or more electrical termination devices; and so arranged that as a unit it can be assembled and handled as one assembly. Also refer to Cable Harness Discussion for additional information.

Hartley Oscillator. An oscillator that uses two series connected inductors in parallel [a tapped coil or split coil] with a capacitor. The feedback point for the Hartley oscillator is between the two inductors as shown in the diagram. The oscillating frequency is determined by the LC circuit.

Hartley Oscillator Circuit
Hartley Oscillator

Hay Bridge. An AC bridge that uses capacitors and resistors to determine the value of an unknown inductor.

HDLC. High-level Data Link Control is a group of protocols for transmitting [synchronous] data Packets between Point-to-Point nodes. Data is organized into a frame in HDLC. HDLC protocol resides with Layer 2 of the OSI model, the data link layer.

PC motherboard

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