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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 180 degrees out of phase to the input signal. 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 function of both temperature and bias current, and so the actual gain is somewhat ... [...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 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 musical effect, particularly with electric guitars. The addition of noise or other outside signals (hum, interference) is not considered di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time Constant
In physics and engineering, the time constant, usually denoted by the Greek letter (tau), is the parameter characterizing the response to a step input of a first-order, linear time-invariant (LTI) system.Concretely, a first-order LTI system is a system that can be modeled by a single first order differential equation in time. Examples include the simplest single-stage electrical RC circuits and RL circuits. The time constant is the main characteristic unit of a first-order LTI system. In the time domain, the usual choice to explore the time response is through the step response to a step input, or the impulse response to a Dirac delta function input. In the frequency domain (for example, looking at the Fourier transform of the step response, or using an input that is a simple sinusoidal function of time) the time constant also determines the bandwidth of a first-order time-invariant system, that is, the frequency at which the output signal power drops to half the value it has at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Art Of Electronics
''The Art of Electronics'', by Paul Horowitz and Winfield Hill, is a popular reference textbook dealing with analog and digital electronics. The first edition was published in 1980, and the 1989 second edition has been regularly reprinted. The third edition was published on April 9, 2015. The author is accepting reports of errata and publishing them, to be corrected in future revisions. Overview The book covers many areas of circuit design, from basic DC voltage, current, and resistance, to active filters and oscillators, to digital electronics, including microprocessors and digital bus interfacing. It also includes discussions of such often-neglected areas as high-frequency, high-speed design techniques and low-power applications. The book includes many example circuits. In addition to having examples of good circuits, it also has examples of bad ideas, with discussions of what makes the good designs good and the bad ones bad. It can be described as a cross between a tex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Winfield Hill
Winfield Hill is the Director of the Electronics Engineering Laboratory at the Rowland Institute at Harvard University. A self-proclaimed "electronics circuit-design guru" and trained physicist and electronic engineer, he co-authored the popular text ''The Art of Electronics ''The Art of Electronics'', by Paul Horowitz and Winfield Hill, is a popular reference textbook dealing with analog and digital electronics. The first edition was published in 1980, and the 1989 second edition has been regularly reprinted. The ...'' with Harvard Physicist Paul Horowitz. Engineering work by Hill in the late 1970s at Harvard led him to found the Sea Data Corporation, which designed instruments for deep-sea oceanography. References #Winfield Hill's Electronics/Engineering Home Page External linksWinfield Hill The Rowland Institute at Harvard 21st-century American engineers Harvard University faculty Living people Year of birth missing (living people) Place of birth missing (livin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul Horowitz
Paul Horowitz (born 1942) is an American physicist and electrical engineer, known primarily for his work in electronics design, as well as for his role in the search for extraterrestrial intelligence (see SETI). Biography At age 8, Horowitz achieved distinction as the world's youngest amateur radio operator. He went on to study physics at Harvard University (B.A., 1965; M.A., 1967; Ph.D., 1970), where he has also spent all of his subsequent career. His early work was on scanning microscopy (using both protons and X-rays). Horowitz has also conducted astrophysical research on pulsars and investigations in biophysics. His interest in practical electronics has led to a handful of inventions, including an automated voting machine and an acoustic mechanism for landmine detection, and an electronic Morse Code/Baudot code keyboard using a diode matrix and 66 TTL integrated circuits for Amateur Radio use. Since 1974 he has taught a practical course in electronics whose lecture no ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parasitic Capacitance
Parasitic capacitance is an 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 non-zero capacitance between any two conductors; this can be significant with closely spaced conductors, such as wires or printed circuit board traces. The parasitic capacitance between the turns of an inductor or other wound component is often described as ''self-capacitance''. However, in electromagnetics, the term self-capacitance more correctly refers to a different phenomenon: the capacitance of a condu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miller Effect
In electronics, the Miller effect accounts for the increase in the equivalent input capacitance of an inverting voltage amplifier due to amplification of the effect of capacitance between the input and output terminals. The virtually increased input capacitance due to the Miller effect 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 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. Miller capacitance was identified in 1920 in triode vacuum tubes by John Milton Miller. History The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Output Impedance
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, thermodynamic, or mechanical prop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Input Impedance
The input impedance of an electrical network is the measure of the opposition to current ( impedance), both static ( resistance) and dynamic ( reactance), into the load network that is ''external'' to the electrical source. The input admittance (the reciprocal of impedance) is a measure of the load'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. 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 would be the same from the perspective of the connection point. So, the voltage across and the current through the input terminals would be identical to the chosen load network. Therefore, the input impedance of the load and the output impedance of the source determine how the source current and voltage change. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hybrid-pi Model
The hybrid-pi model is a popular circuit model used for analyzing the small signal behavior of bipolar junction and field effect transistors. Sometimes it is also called Giacoletto model because it was introduced by 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 elements. BJT parameters The hybrid-pi model is a linearized two-port network A two-port network (a kind of four-terminal network or quadripole) is an electrical network ( circuit) or device with two ''pairs'' of terminals to connect to external circuits. Two terminals constitute a port if the currents applied to them sati ... approximation to the BJT using the small-signal base-emitter voltage, \scriptstyle v_\text, and collector-emitter voltage, \scriptstyle v_\text, as independent variables, and the small-signal base current, \scriptstyle i_\te ... [...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 discovering the negative feedback amplifier in 1927. To some, his discovery 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 electroni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
