|
Common Emitter
In electronics, a common-emitter amplifier is one of three basic single-stage bipolar-junction-transistor (BJT) amplifier topologies, typically used as a voltage amplifier. It offers high current gain (typically 200), medium input resistance and a high output resistance. The output of a common emitter amplifier is inverted; i.e. for a sine wave input signal, the output signal is 180 degrees out of phase with respect to the input. In this circuit, the base terminal of the transistor serves as the input, the collector is the output, and the emitter is ''common'' to both (for example, it may be tied to ground reference or a power supply rail), hence its name. The analogous FET circuit is the common-source amplifier, and the analogous tube circuit is the common-cathode amplifier. Emitter degeneration Common-emitter amplifiers give the amplifier an inverted output and can have a very high gain that may vary widely from one transistor to the next. The gain is a strong f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NPN Common Emitter
{{disambiguation ...
NPN may refer to: Science and technology * Next Protocol Negotiation, in computer networking * Non-protein nitrogen, an animal feed component * NPN transistor * Normal Polish notation, in mathematics Organisations * National Party of Nigeria, a former political party * New Politics Network, a UK think tank Other uses * Natural Health Product Number, required by the Canadian Natural Health Products Directorate The Natural Health Products Directorate (NHPD) is the division of the Health Products and Food Branch of Health Canada that is responsible for implementation of the Natural Health Product Regulations, including Good Manufacturing Practices, for Nat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BIBO Stability
In signal processing, specifically control theory, bounded-input, bounded-output (BIBO) stability is a form of stability for signals and systems that take inputs. If a system is BIBO stable, then the output will be bounded for every input to the system that is bounded. A signal is bounded if there is a finite value B > 0 such that the signal magnitude never exceeds B, that is :For discrete-time signals: \exists B \forall n(\ , y \leq B) \quad n \in \mathbb :For continuous-time signals: \exists B \forall t(\ , y(t), \leq B) \quad t \in \mathbb Time-domain condition for linear time-invariant systems Continuous-time necessary and sufficient condition For a continuous time linear time-invariant (LTI) system, the condition for BIBO stability is that the impulse response, h(t) , be absolutely integrable, i.e., its L1 norm exists. : \int_^\infty \left, h(t)\\,\mathordt = \, h \, _1 \in \mathbb Discrete-time sufficient condition For a discrete time LTI system, the condition f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parasitic Capacitance
Parasitic capacitance or stray capacitance is the unavoidable and usually unwanted capacitance that exists between the parts of an electronic component or circuit simply because of their proximity to each other. When two electrical conductors at different voltages are close together, the electric field between them causes electric charge to be stored on them; this effect is capacitance. All practical circuit elements such as inductors, diodes, and transistors have internal capacitance, which can cause their behavior to depart from that of ideal circuit elements. Additionally, there is always some capacitance between any two conductors; this can be significant with closely spaced conductors, such as adjacent wires or printed circuit board traces. The parasitic capacitance between the turns of an inductor (e.g. Figure 1) or other wound component is often described as ''self-capacitance''. However, in electromagnetics, the term self-capacitance more correctly refers to a diffe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miller Effect
In electronics, the Miller effect (named after its discoverer John Milton Miller) accounts for the increase in the equivalent input capacitance of an inverting voltage amplifier due to amplification of the effect of capacitance between the amplifier's input and output terminals, and is given by :C_=C (1+A_v)\, where -A_v is the voltage gain of the inverting amplifier (A_v positive) and C is the feedback capacitance. Although the term ''Miller effect'' normally refers to capacitance, any impedance connected between the input and another node exhibiting gain can modify the amplifier input impedance via this effect. These properties of the Miller effect are generalized in the Miller theorem. The Miller capacitance due to undesired parasitic capacitance between the output and input of active devices like transistors and vacuum tubes is a major factor limiting their gain at high frequencies. History When Miller published his work in 1919, he was working on vacuum tube triodes. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Output Impedance
In electrical engineering, the output impedance of an electrical network is the measure of the opposition to current flow ( impedance), both static ( resistance) and dynamic ( reactance), into the load network being connected that is ''internal'' to the electrical source. The output impedance is a measure of the source's propensity to drop in voltage when the load draws current, the source network being the portion of the network that transmits and the load network being the portion of the network that consumes. Because of this the output impedance is sometimes referred to as the source impedance or internal impedance. Description All devices and connections have non-zero resistance and reactance, and therefore no device can be a perfect source. The output impedance is often used to model the source's response to current flow. Some portion of the device's measured output impedance may not physically exist within the device; some are artifacts that are due to the chemical, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Input Impedance
In electrical engineering, the input impedance of an electrical network is the measure of the opposition to current ( impedance), both static ( resistance) and dynamic ( reactance), into a load network or circuit that is ''external'' to the electrical source network. The input admittance (the reciprocal of impedance) is a measure of the load network's propensity to draw current. The source network is the portion of the network that transmits power, and the load network is the portion of the network that consumes power. For an electrical property measurement instrument like an oscilloscope, the instrument is a load circuit to an electrical circuit (source circuit) to be measured, so the input impedance is the impedance of the instrument seen by the circuit to be measured. Input impedance If the load network were replaced by a device with an output impedance equal to the input impedance of the load network (equivalent circuit), the characteristics of the source-load network w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hybrid-pi Model
Hybrid-pi is a popular Electronic circuit, circuit model used for analyzing the small signal behavior of Bipolar junction transistor, bipolar junction and Field-effect transistor, field effect transistors. Sometimes it is also called Giacoletto model because it was introduced by Lawrence J. Giacoletto, L.J. Giacoletto in 1969. The model can be quite accurate for low-frequency circuits and can easily be adapted for higher frequency circuits with the addition of appropriate inter-electrode capacitances and other Parasitic element (electrical networks), parasitic elements. BJT parameters The hybrid-pi model is a linearized two-port network approximation to the BJT using the small-signal base-emitter voltage, \textstyle v_\text, and collector-emitter voltage, \textstyle v_\text, as independent variables, and the small-signal base current, \textstyle i_\text, and collector current, \textstyle i_\text, as dependent variables. A basic, low-frequency hybrid-pi model for the bipolar tr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harold Stephen Black
Harold Stephen Black (April 14, 1898 – December 11, 1983) was an American electrical engineer, who revolutionized the field of applied electronics by inventing the negative feedback amplifier in 1927. To some, his invention is considered the most important breakthrough of the twentieth century in the field of electronics, since it has a wide area of application. This is because all electronic devices (vacuum tubes, bipolar transistors and MOS transistors) are inherently nonlinear, but they can be made substantially linear with the application of negative feedback. Negative feedback works by sacrificing gain for higher linearity (or in other words, smaller distortion/intermodulation). By sacrificing gain, it also has an additional effect of increasing the bandwidth of the amplifier. However, a negative feedback amplifier can be unstable such that it may oscillate. Once the stability problem is solved, the negative feedback amplifier is extremely useful in the field of electronics. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Negative Feedback
Negative feedback (or balancing feedback) occurs when some function (Mathematics), function of the output of a system, process, or mechanism is feedback, fed back in a manner that tends to reduce the fluctuations in the output, whether caused by changes in the input or by other disturbances. Whereas positive feedback tends to instability via exponential growth, oscillation or chaos theory, chaotic behavior, negative feedback generally promotes stability. Negative feedback tends to promote a settling to List of types of equilibrium, equilibrium, and reduces the effects of perturbations. Negative feedback loops in which just the right amount of correction is applied with optimum timing, can be very stable, accurate, and responsive. Negative feedback is widely used in Mechanical engineering, mechanical and electronic engineering, and it is observed in many other fields including biology, chemistry and economics. General negative feedback systems are studied in Control engin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transconductance
Transconductance (for transfer conductance), also infrequently called mutual conductance, is the electrical characteristic relating the current through the output of a device to the voltage across the input of a device. Conductance is the reciprocal of resistance. Transadmittance (or transfer admittance) is the AC equivalent of transconductance. Definition Transconductance is very often denoted as a conductance, , with a subscript, , for ''mutual''. It is defined as follows: : g_\text = \frac For small signal alternating current, the definition is simpler: : g_\text = \frac The SI unit for transconductance is the siemens, with the symbol S, as in conductance. Transresistance Transresistance (for transfer resistance), also infrequently referred to as mutual resistance, is the dual of transconductance. It refers to the ratio between a change of the voltage at two output points and a related change of current through two input points, and is denotated as : : r_\text = \ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resistor
A resistor is a passive two-terminal electronic component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active elements, and terminate transmission lines, among other uses. High-power resistors that can dissipate many watts of electrical power as heat may be used as part of motor controls, in power distribution systems, or as test loads for generators. Fixed resistors have resistances that only change slightly with temperature, time or operating voltage. Variable resistors can be used to adjust circuit elements (such as a volume control or a lamp dimmer), or as sensing devices for heat, light, humidity, force, or chemical activity. Resistors are common elements of electrical networks and electronic circuits and are ubiquitous in electronic equipment. Practical resistors as discrete components can be composed of various compounds and forms. Resisto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distortion
In signal processing, distortion is the alteration of the original shape (or other characteristic) of a signal. In communications and electronics it means the alteration of the waveform of an information-bearing signal, such as an audio signal representing sound or a video signal representing images, in an electronic device or communication channel. Distortion is usually unwanted, and so engineers strive to eliminate or minimize it. In some situations, however, distortion may be desirable. For example, in noise reduction systems like the Dolby noise-reduction system, Dolby system, an audio signal is deliberately distorted in ways that emphasize aspects of the signal that are subject to electrical noise, then it is symmetrically "undistorted" after passing through a noisy communication channel, reducing the noise in the received signal. Distortion is also used as a Distortion (music), musical effect, particularly with electric guitars. The addition of Electronic noise, noise o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
