Technical Engineering Definitions
"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"

'Ma' to 'Md', 'Me' to 'Mh', 'Mi' to 'Mn', 'Mo' to 'Mod',
'Mod' to 'Mou', 'Mov' to 'Mz',

Machine Language. A language that need not be modified, translated, or interpreted before it can be used by the processor for which it was designed.

Machine Tool Transformer. See Control Circuit Transformer.

Magic-T Junction. A hybrid style of waveguide combination of H-type and E-type T-junctions.

Magnet Wire. Wire coated with an enamel insulation and used in coils, relays, transformers, motor windings, and so forth. Also refer to MIL J-W-1177; Wire, Magnet, Electrical, General Specification [cancelled in 2000, with no replacement]. A single solid insulated electrical conductor or various cross-sectional configurations. It must be specifically designed for use in electromagnetic circuits.

Magnetic Amplifier. An electromagnetic device that uses one or more saturable reactors to obtain a large power gain. This device is used in servosystems requiring large amounts of power to move heavy loads.

Magnetic Circuit. The complete closed path taken by magnetic flux.

Magnetic Field. The region in which the magnetic forces created by a permanent magnet or by a current-carrying conductor or coil can be detected. The field that is produced when current flows through a conductor or antenna.

Magnetic Flux. The magnetic filed or induction in a material.

Magnetic Head. A device that records, reads or erases data on a magnetic tape.

Magnetic Hysteresis Loop. See Hysteresis Loop.

Magnetic induction. Generating a voltage in a circuit by the creation of relative motion between a magnetic field and the circuit. The relative motion can be the result of physical movement or the rise and fall of a magnetic field created by a changing current.

Magnetic Lines of Force. Imaginary lines used for convenience to designate the direction in which magnetic forces are acting as a result of magnetomotive force.

Magnetic Microphone. A microphone in which the sound waves vibrate a moving armature. The armature consists of a coil wound on the armature and located between the pole pieces of a permanent magnet. The armature is mechanically linked to the diaphragm.

Magnetic Poles. The section of a magnet where the flux lines are concentrated; also where they enter and leave the magnet.

Magnetic Trip Element. A circuit breaker trip element that uses the increasing magnetic attraction of a coil with increased current to open the circuit.

Magnetism. The property possessed by certain materials by which these materials can exert mechanical force on neighboring masses of magnetic materials and can cause currents to be induced in conducting bodies moving relative to the magnetized bodies.

Magnetron Oscillator. An electron tube that provides a high power output. Theory of operation is based on interaction of electrons with the crossed electric and magnetic fields in a resonant cavity.

Magnitude Comparator. A circuit that compares one value with another. In digital logic a circuit that compares two binary numbers. Also refer to IC Magnitude Comparator Chips [for schematic and part numbers].

Main Lobe. Of an antenna radiation pattern, the lobe containing the maximum power. See the diagram of a Main Lobe in the dictionary of antenna terms.

Make-Before-Break. [Shorting Switch] A switch that makes the new connection before it breaks the previous connection.

Manchester Encoding. A method of binary encoding, see Manchester Encoding listing.

Mark. An interval during which a signal is present. Also the presence of an RF signal in cw keying. The key-closed condition (presence of data) in communications systems. A high level in an RS232 System [the opposite of a Space].

Marking. How a component or device is marked with a part number, date code, and place of manufacturer [depending on available space]. Same as the term Part Marking, but the government uses Marking.

Mask. A logical operation on one or more data bits in a word where one data word is used to change another data word.

Exclusive OR gate mask circuit
Masking Circuit

The Masking circuit above uses a predefined mask word to change the incoming Data into an output that depends both on the incoming data and the stored mask. In this case any incoming data bit that is a one is changed to a zero if the mask is also one.

Mask ROM. A Read Only Memory IC that has been pre-programmed at the factor before the device was shipped. A ROM that has had a mask applied to it. Also refer to ROM IC Vendors.

Master Oscillator. In a transmitter, the oscillator that establishes the carrier frequency of the output. A highly stable oscillator.

Master Oscillator Power Amplifier. [MOPA] A transmitter in which the oscillator is isolated from the antenna by a power amplifier.

Master-Slave Flip Flop. A circuit formed by two flip flops, the Master flip flop receives incoming data on the leading edge clock pulse and provides the Q output to the Slave flip flop which clocks in the data on the trailing edge of the clock. The output is the Q [or Q-not] from the slave flip flop. Examples include the 4027, CMOS Dual J-K Master-Slave Flip Flop, or TTL devices; 5476, 5473, and 5472 [shown in the side-bar].

Master-Slave Timing. Timing in which one station or node supplies the timing reference for all other interconnected stations or nodes.

Matched Load. A device or component used to terminate a transmission line so that all of the incoming energy is absorbed. Also refer to the section covering Transmission Line Termination Methods.

Matching Transformer. A transformer used to match the impedance between circuits separated by the transformer.

Maximal Length Sequence. A pseudo-random sequence of length 2N-1 generated by a shift register of length N.

Maximum Clock Frequency. [fmax] The highest rate at which the clock input of a bistable circuit can be driven through its required sequence and still maintain stable transitions of logic level at the output.

Maximum Limit. The highest-magnitude limit of a range of some quantity. For logic levels the Maximum Limit is the most positive (least negative) limit.

Maximum Power Dissipation. The maximum total power dissipation a component will operate at within specification.

Maximum Ratings. The maximum operating characteristics a device will operate at with out damage, at some operating temperature.

Maximum Safe Operating Area. Same as Safe Operating Area [SOA] which is the area bounded under a curve such that the combination of maximum current and maximum voltage are not exceeded. The graph to the right shows an example which includes individual lines for current x voltage duration. DC is the lowest blue line, orange is 1000mS, green is 100mS, pink is 10mS and so on. So continuous operation [DC] results in the smallest SOA, while larger voltages or currents may be used as the duration is decreased. Another example of a 2N3637 Safe Operating Area Graph.

Maximum Usable Frequency. The maximum frequency that can be used for communications between two locations for a given time of day and a given angle of incidence.

Maxterm. A sum term containing every variable once and only once.

Maxwell. The unit of magnetic flux.

Maxwell Bridge. A four-arm [Wheatstone Bridge] ac bridge used to measure inductance in terms of resistance and capacitance.

PC motherboard

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