Electronic Technical 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"

J1850. An automotive bus used for diagnostics and data sharing applications in vehicles. J1850 may use either a single or differential wire approach. Read more about the J1850 Bus Description.

Jabber. A condition wherein a station transmits for a period of time longer than the maximum permissible packet length, usually due to a fault condition. In local area networks, transmission by a data station beyond the time interval allowed by the protocol.

Jack. A socket. A receptacle. The fixed portion of a two connector system. The female end of a mating connector which accepts a Plug. An example Banana Jack, or panel-mount Test Jack is shown in the graphic. Also see Jack & Plug Vendors.

Female Jack Connector
Panel Mount Test Jack

Jacket. The outermost layer of insulating material of a cable or harness. The outer sheath which protects a cable. The outer sheath or covering material,such as natural or synthetic rubber, lead sheath,steel tape, or a thermoplastic compound, applied over a single-insulated conductor or over an assembly of insulated conductors for protection against crushing,cutting,and abrasion of the conductors and their insulation.

Jack Screw. A threaded jack. A female post used to accept a bolt or other threaded part. Refer to the jack-post graphic in the right side-bar. A locking device specifically designed to secure engaged electrical connectors. Its mating end is either internally or externally threaded.

Jacketed Twisted Pair Cable
Jacketed Twisted Pair Cable

Jacketed Cable. A bundle of insulated wires encased in a common sheath. Also refer to Cable Armor.

Jam Nut. A jam nut is a low profile type of nut, typically half as tall as a standard nut. It is commonly used as a type of locknut, where it is "jammed" up against a standard nut to lock the two in place. It is also used in situations where a standard nut would not fit.

JAN. Joint Army Navy specification. There are five quality levels, from the lowest level to the highest level are: JAN, JANTX, JANTXV, JANJ, and JANS. Eight radiation hardness assurance (RHA) levels are provided for the JANTXV and JANS quality levels. JANKC is intended for space applications and JANHC is intended for standard military applications.

JEDEC. Joint Electron Device Engineering Council.

JFET. Junction FET [Field Effect Transistor], a voltage controlled transistor and not current controlled. A transistor in which the conduction is due entirely to the flow of majority carriers through a conduction channel controlled by an electric field arising from a voltage applied between the gate and source terminals. [FET Manufacturers] and vendors.
An N-Channel FET is shown to the right.

N-Channel JFET Symbol

Jitter. Jitter is the difference [deviation] between the expected occurrence of a signal edge and the time the edge actually occurs [phase variation]. Jitter may also be expressed as the movement of a signal edge from its ideal position in time [the expected position]. Abrupt and unwanted variations of one or more signal characteristics, such as the interval between successive pulses, the amplitude of successive cycles, or the frequency or phase of successive cycles. Read more on Signal Jitter.

Jitter Tolerance. The amount of jitter that a system could tolerate before errors occur due to jitter.

JK Flip Flop. A style of flip flop that has a J input and a K input, and also may have a Set [S] and Reset [R] input. No change occurs when J and K are low. When the K is low the output is low and when the J is low the output goes high. When both J and K are high the output toggles. Truth Table to right. Examples ICs; 7473, 7476, 74107, 7470.

JK Flip Flop Symbol

JTAG. Joint Test Action Group. IEEE Std 1149.1-1990, Test Access Port and Boundary-Scan Architecture (3) The JTAG interface is a serial bus with four signals: Test Clock (TCK), Test Mode Select (TMS), Test Data Input (TDI), and Test Data Output (TDO). Read more to include the JTAG Bus Description.

Johnson Counter. A style of ring counter that recycles base on the inverted output being feed back to the input.

Johnson Noise. Thermal Noise.

Joule. The work done by a force of one newton acting through a distance of one meter.

Joystick. A peripheral device used with personal computers to translate physical movement in two axis into electrical signals used by the computer. Also see a common JoyStick Pin out.

Jumper. A short length of wire used to complete a circuit. A small plastic case with two female receptacles [shunt] used to short two adjacent contacts or pins, normally on 0.1 inch centers. The term may also describe a Zero Ohm Resistor. A jumper is usually used with a 2-pin header. Header Manufacturers.
The graphic shows two male board headers, with jumpers or shunts installed on three pairs of the pins.

Un-shrouded Header Jumper Block with Shunt
Jumper Block

Junction. The connection between two or more conductors. The contact between two dissimilar metals or materials, as in a thermocouple. A region of transition between semiconductor layers, such as a p/n junction, which goes from a region that has a high concentration of acceptors (p-type) to one that has a high concentration of donors (n-type).

Junction Box. A box with a cover that serves the purpose of joining different runs of wire or cable and provides space for the connection and branching of the enclosed conductors. An enclosure of other than cast metal designed to house, mount, and protect, but does not include wiring connections or electrical devices such as terminals, terminal boards, switches, jacks, fuse-holders, connectors, or circuit breakers.

Junction Diode. A two-terminal device containing a single crystal of semi-conducting material that ranges from P-type at one terminal to N-type at the other. Also refer to Diode Manufacturers. A semiconductor device with a junction and a built-in potential that passes current better in one direction than the other. All solar cells are junction diodes.

Junction FET. JFET [Field Effect Transistor]. Also see FET Manufacturers.

Junction Transistor. A bipolar transistor constructed from interacting PN junctions. The term is used to distinguish junction transistors from other types, such as field-effect and point-contact. Reference; Transistor Terms, and BJT Manufacturers.

Just-a-Bunch-Of-Disks. [JBOD] A collection of hard disk drives connected in a Redundant Array of Independent Disks [RAID]. A group of disks that are used in a system that may be used separately or together.

PC motherboard

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