Dictionary of Electronics "n-type" to "overload"

n-type semiconductor A semiconductor compound formed by doping an intrinsic semiconductor with a pentavalent element. An n-type material contains an excess of conduction band electrons. negative Terminal that has an excess of electrons. negative charge A charge that has more electrons than protons negative feedback A feedback signal 180° out of phase with an amplifier input signal. Used to increase amplifier stability, bandwidth and input impedance. Also reduces distortion. negative ground A system where the negative terminal of the source is connected to the system's metal chassis. negative ion An atom having a greater number of electrons in orbit than there are protons in the nucleus. negative resistance A resistance such that when the current through it increases the voltage drop across the resistance decreases. negative temperature coefficient A term used to describe a component whose resistance or capacitance decreases when temperature increases. neon bulb Glass envelope filled with neon gas which when ionized by an applied voltage will glow red. network Combination of interconnected components, circuits or systems. neutral A terminal, point or object with balanced charges. Neither positive or negative. neutral atom An atom in which the number of negative charges (electrons in orbit) is equal to the number of positive charges (protons in the nucleus). neutral wire The conductor of a polyphase circuit or a single-phase three wire circuit that is intended to have a ground potential. The potential difference between the neutral and each of the other conductors are approximately equal in magnitude and equally spaced in phase. neutron Subatomic particle in the nucleus of an atom and having no electrical charge. nickel-cadmium cell A secondary cell that uses a nickel oxide positive electrode and a cadmium negative electrode. node Junction or branch point in a circuit. noise Unwanted electromagnetic radiation within an electrical or mechanical system. An operational amplifier circuit having no phase inversion between the input and output. non-inverting input The terminal on an operational amplifier that is identified by a plus sign. non-linear scale A scale in which the divisions are not equally spaced. normall closed Designation which states that the contacts of a switch or relay are closed or connected when at rest. When activated, the contacts open or separated. normally open Designation which states that the contacts of a switch or relay are normally open or not connected. When activated the contacts close or become connected. north pole Pole of a magnet out of which magnetic lines of force are assumed to originate. Norton's theorem Any network of voltage sources and resistors can be replace by a single current source in parallel with a single resistor. notch filter A filter which blocks a narrow band of frequencies and passes all frequencies above and below the band. npn transistor A bipolar junction transistor in which a p-type base element is sandwiched between an n-type emitter and an n-type collector. nucleus Core of an atom. The nucleus contains both positive (protons) and neutral (neutrons) subatomic particles. O octave Interval between two sounds whose fundamental frequencies differ by a ratio of 2 to 1. 440 Hz. is one octave above 220 Hz. offset null An op amp control pin used to eliminate the effects of internal component voltages on the output of the device. ohm Unit of resistance symbolized by the Greek capital letter omega (W). ohmmeter Device used to measure electrical resistance. Ohm's law Relationship between voltage, current and resistance. Ohm's law states that current in a resistance varies in direct proportion to voltage applied and inversely proportional to resistance. Ohms per volt Refers to a value of ohms per volt of full scale defection for a moving coil meter movement. The number of ohms per volt is the reciprocal of the amount of current required to produce full scale deflection of the needle. A meter requiring 50 microamps for full scale deflection has an internal resistance of 20 kW per volt. The higher the ohms per volt rating, the more sensitive the meter. one-shot Monostable multivibrator. op-amp Abbreviation for operational amplifier. open loop gain Gain of an amplifier when no feedback is present. open loop mode An amplifier circuit having no means of comparing the output with the input. (No feedback.) operational amplifier A high gain DC amplifier that has a high input impedance and a low output impedance. Op-amps are the most basic type of linear integrated circuits. oscillate To produce a continuous output waveform without an input signal present. oscillator An electronic circuit that produces a continuous output waveform with only DC applied. oscilloscope An instrument used to display a signal graphically. Shows signal amplitude, period and waveshape in addition to any DC voltage present. A multiple trace oscilloscope can show two or more waveforms at the same time for phase comparison and timing measurements. out of phase When the maximum and minimum points of two or more waveshpes do not occur at the same time. output Terminal at which a component, circuit or piece of equipment delivers current, voltage or power. output impedance Impedance measured across the output terminals of a device without a load connected. output power Amount of power a component, circuit or system can deliver to a load. overload Codition that occurs when the load is greater than the system was designed to handle. (Load resistance too small, load current too high.) Overload results in waveform distortion and/or overheating. overload protection Protective device such as a fuse or circuit breaker that outomatically disconnects a load when current exceeds a predetermined value.