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Chopper (electronics)
In electronics, a chopper circuit is any of numerous types of electronic switching devices and circuits used in power control and signal applications. A chopper is a device that converts fixed DC input to a variable DC output voltage directly. Essentially, a chopper is an electronic switch that is used to interrupt one signal under the control of another. In power electronics applications, since the switching element is either fully on or fully off, its losses are low and the circuit can provide high efficiency. However, the current supplied to the load is discontinuous and may require smoothing or a high switching frequency to avoid undesirable effects. In signal processing circuits, use of a chopper stabilizes a system against drift of electronic components; the original signal can be recovered after amplification or other processing by a synchronous demodulator that essentially un-does the "chopping" process. Comparison (step down chopper and step up chopper) Comparison b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Direct Current
Direct current (DC) is one-directional electric current, flow of electric charge. An electrochemical cell is a prime example of DC power. Direct current may flow through a conductor (material), conductor such as a wire, but can also flow through semiconductors, electrical insulation, insulators, or even through a vacuum as in electron beam, electron or ion beams. The electric current flows in a constant direction, distinguishing it from alternating current (AC). A archaism, term formerly used for this type of current was galvanic current. The abbreviations ''AC'' and ''DC'' are often used to mean simply ''alternating'' and ''direct'', as when they modify ''Electric current, current'' or ''voltage''. Direct current may be converted from an alternating current supply by use of a rectifier, which contains Electronics, electronic elements (usually) or electromechanical elements (historically) that allow current to flow only in one direction. Direct current may be converted into alt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IEEE
The Institute of Electrical and Electronics Engineers (IEEE) is an American 501(c)(3) organization, 501(c)(3) public charity professional organization for electrical engineering, electronics engineering, and other related disciplines. The IEEE has a corporate office in New York City and an operations center in Piscataway, New Jersey. The IEEE was formed in 1963 as an amalgamation of the American Institute of Electrical Engineers and the Institute of Radio Engineers. History The IEEE traces its founding to 1884 and the American Institute of Electrical Engineers. In 1912, the rival Institute of Radio Engineers was formed. Although the AIEE was initially larger, the IRE attracted more students and was larger by the mid-1950s. The AIEE and IRE merged in 1963. The IEEE is headquartered in New York City, but most business is done at the IEEE Operations Center in Piscataway, New Jersey, opened in 1975. The Australian Section of the IEEE existed between 1972 and 1985, after which it s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vibrator (electronic)
A vibrator is an electromechanical device that takes a DC electrical supply and converts it into pulses that can be fed into a transformer. It is similar in purpose (although greatly different in operation) to the Solid-state electronics, solid-state power inverter. Before the development of switch-mode power supplies and the introduction of semiconductor electronics, semiconductor devices operating off low voltage, there was a requirement to generate voltages of about 50 to 250 V DC from a vehicle's Lead-acid battery, battery. A vibrator was used to provide pulsating DC which could be converted to a higher voltage with a transformer, Rectifier, rectified, and filtered to create higher-voltage DC. It is essentially a relay using normally closed contacts to supply power to the relay coil, thus immediately breaking the connection, only to be reconnected very quickly through the normally closed contacts. It happens so rapidly it vibrates, and sounds like a buzzer. This same rapidly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Braking Chopper
Braking choppers, sometimes also referred to as Braking units, are used in the DC voltage intermediate circuits of frequency converters to control voltage when the load feeds energy back to the intermediate circuit. This arises, for example, when a magnetized Electric motor, motor is being rotated by an overhauling load and so functions as a Electrical generator, generator feeding power to the DC voltage intermediate circuit.R. Krishnan, 2001 "Electric Motor Drives: Modeling, Analysis, and Control", Prentice Hall They are an application of the chopper (electronics), chopper principle, using the on-off control of a switching device. Operation A braking chopper is an magnetical switch that limits the DC bus voltage by switching the braking energy to a resistor where the braking energy is converted to heat. Braking choppers are automatically activated when the actual DC bus voltage exceeds a specified level depending on the nominal voltage of the variable-frequency drive Benefits * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Duty Cycle
A duty cycle or power cycle is the fraction of one period in which a signal or system is active. Duty cycle is commonly expressed as a percentage or a ratio. A period is the time it takes for a signal to complete an on-and-off cycle. As a formula, a duty cycle (%) may be expressed as: :D = \frac \times 100\% Equally, a duty cycle (ratio) may be expressed as: :D = \frac where D is the duty cycle, PW is the pulse width (pulse active time), and T is the total period of the signal. Thus, a 60% duty cycle means the signal is on 60% of the time and off 40% of the time. The "on time" for a 60% duty cycle could be a fraction of a second, a day, or even a week, depending on the length of the period. Duty cycles can be used to describe the percent time of an active signal in an electrical device such as the power switch in a switching power supply or the firing of action potentials by a living system such as a neuron. Some publications use \alpha as the symbol for duty cycle. As a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voltage
Voltage, also known as (electrical) potential difference, electric pressure, or electric tension, is the difference in electric potential between two points. In a Electrostatics, static electric field, it corresponds to the Work (electrical), work needed per unit of Electric charge, charge to move a positive Test particle#Electrostatics, test charge from the first point to the second point. In the SI unit, International System of Units (SI), the SI derived unit, derived unit for voltage is the ''volt'' (''V''). The voltage between points can be caused by the build-up of electric charge (e.g., a capacitor), and from an electromotive force (e.g., electromagnetic induction in a Electric generator, generator). On a macroscopic scale, a potential difference can be caused by electrochemical processes (e.g., cells and batteries), the pressure-induced piezoelectric effect, and the thermoelectric effect. Since it is the difference in electric potential, it is a physical Scalar (physics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inductor
An inductor, also called a coil, choke, or reactor, is a Passivity (engineering), passive two-terminal electronic component, electrical component that stores energy in a magnetic field when an electric current flows through it. An inductor typically consists of an insulated wire wound into a Electromagnetic coil, coil. When the current flowing through the coil changes, the time-varying magnetic field induces an electromotive force (''emf'') (voltage) in the conductor, described by Faraday's law of induction. According to Lenz's law, the induced voltage has a polarity (direction) which opposes the change in current that created it. As a result, inductors oppose any changes in current through them. An inductor is characterized by its inductance, which is the ratio of the voltage to the rate of change of current. In the International System of Units (SI), the unit of inductance is the Henry (unit), henry (H) named for 19th century American scientist Joseph Henry. In the measurement ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kirchoff Voltage Law
Kirchhoff's circuit laws are two equalities that deal with the current and potential difference (commonly known as voltage) in the lumped element model of electrical circuits. They were first described in 1845 by German physicist Gustav Kirchhoff. This generalized the work of Georg Ohm and preceded the work of James Clerk Maxwell. Widely used in electrical engineering, they are also called Kirchhoff's rules or simply Kirchhoff's laws. These laws can be applied in time and frequency domains and form the basis for network analysis. Both of Kirchhoff's laws can be understood as corollaries of Maxwell's equations in the low-frequency limit. They are accurate for DC circuits, and for AC circuits at frequencies where the wavelengths of electromagnetic radiation are very large compared to the circuits. Kirchhoff's current law This law, also called Kirchhoff's first law, or Kirchhoff's junction rule, states that, for any node (junction) in an electrical circuit, the sum of currents f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Input Offset Voltage
The input offset voltage (V_) is a parameter defining the differential DC voltage required between the inputs of an amplifier, especially an operational amplifier (op-amp), to make the output zero (for voltage amplifiers, 0 volts with respect to ground or between differential outputs, depending on the output type). Details An ideal op-amp amplifies the differential input; if this input difference is 0 volts (i.e. both inputs are at the same voltage), the output should be zero. However, due to manufacturing process, the differential input transistors of real op-amps may not be exactly matched. This causes the output to be zero at a non-zero value of differential input, called the input offset voltage. Typical values for V_ are around 1 to 10 mV for cheap commercial-grade op-amp integrated circuits (IC). This can be reduced to several microvolts if nulled using the IC's offset null pins or using higher-quality or laser-trimmed devices. However, the input offset voltage value may dr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hall Effect Sensor
A Hall effect sensor (also known as a Hall sensor or Hall probe) is any sensor incorporating one or more Hall elements, each of which produces a voltage proportional to one axial component of the Magnetic field#The B-field, magnetic field vector using the Hall effect (named for physicist Edwin Hall). Hall sensors are used for proximity sensing, positioning (navigation), positioning, Speed limit enforcement, speed detection, and current sensing applications and are common in industrial and consumer applications. Hundreds of millions of Hall sensor integrated circuits (ICs) are sold each year by about 50 manufacturers, with the global market around a billion United States dollar, dollars. Principles In a Hall sensor, a fixed DC current, DC bias current is applied along one axis across a thin strip of metal called the Hall element transducer. Sensing electrodes on opposite sides of the Hall element along ''another'' axis measure the difference in electric potential (voltage) ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pico-
A metric prefix is a unit prefix that precedes a basic unit of measure to indicate a multiple or submultiple of the unit. All metric prefixes used today are decadic. Each prefix has a unique symbol that is prepended to any unit symbol. The prefix '' kilo'', for example, may be added to ''gram'' to indicate ''multiplication'' by one thousand: one kilogram is equal to one thousand grams. The prefix '' milli'', likewise, may be added to ''metre'' to indicate ''division'' by one thousand; one millimetre is equal to one thousandth of a metre. Decimal multiplicative prefixes have been a feature of all forms of the metric system, with six of these dating back to the system's introduction in the 1790s. Metric prefixes have also been used with some non-metric units. The SI prefixes are metric prefixes that were standardised for use in the International System of Units (SI) by the International Bureau of Weights and Measures (BIPM) in resolutions dating from 1960 to 2022. Since 2009, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
