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Dummy Antenna
A dummy load is a device used to simulate an electrical load, usually for testing purposes. In radio a dummy antenna is connected to the output of a radio transmitter and electrically simulates an antenna, to allow the transmitter to be adjusted and tested without radiating radio waves. In audio systems, a dummy load is connected to the output of an amplifier to electrically simulate a loudspeaker, allowing the amplifier to be tested without producing sound. Load banks are connected to electrical power supplies to simulate the supply's intended electrical load for testing purposes. Radio In radio this device is also known as a dummy antenna or a radio frequency termination. It is a device, usually a resistor, used in place of an antenna to aid in testing a radio transmitter. It is substituted for the antenna while one adjusts the transmitter, so that no radio waves are radiated so that the transmitter does not interfere with other radio transmitters during the adjustments. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shortwave
Shortwave radio is radio transmission using shortwave (SW) radio frequencies. There is no official definition of the band, but the range always includes all of the high frequency band (HF), which extends from 3 to 30 MHz (100 to 10 metres); above the medium frequency band (MF), to the bottom of the VHF band. Radio waves in the shortwave band can be reflected or refracted from a layer of electrically charged atoms in the atmosphere called the ionosphere. Therefore, short waves directed at an angle into the sky can be reflected back to Earth at great distances, beyond the horizon. This is called skywave or "skip" propagation. Thus shortwave radio can be used for communication over very long distances, in contrast to radio waves of higher frequency, which travel in straight lines (line-of-sight propagation) and are limited by the visual horizon, about 64 km (40 miles). Shortwave broadcasts of radio programs played an important role in the early days of radio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat Sink
A heat sink (also commonly spelled heatsink) is a passive heat exchanger that transfers the heat generated by an electronic or a mechanical device to a fluid medium, often air or a liquid coolant, where it is dissipated away from the device, thereby allowing regulation of the device's temperature. In computers, heat sinks are used to cool CPUs, GPUs, and some chipsets and RAM modules. Heat sinks are used with high-power semiconductor devices such as power transistors and optoelectronics such as lasers and light-emitting diodes (LEDs), where the heat dissipation ability of the component itself is insufficient to moderate its temperature. A heat sink is designed to maximize its surface area in contact with the cooling medium surrounding it, such as the air. Air velocity, choice of material, protrusion design and surface treatment are factors that affect the performance of a heat sink. Heat sink attachment methods and thermal interface materials also affect the die temperature of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat
In thermodynamics, heat is defined as the form of energy crossing the boundary of a thermodynamic system by virtue of a temperature difference across the boundary. A thermodynamic system does not ''contain'' heat. Nevertheless, the term is also often used to refer to the thermal energy contained in a system as a component of its internal energy and that is reflected in the temperature of the system. For both uses of the term, heat is a form of energy. An example of formal vs. informal usage may be obtained from the right-hand photo, in which the metal bar is "conducting heat" from its hot end to its cold end, but if the metal bar is considered a thermodynamic system, then the energy flowing within the metal bar is called internal energy, not heat. The hot metal bar is also transferring heat to its surroundings, a correct statement for both the strict and loose meanings of ''heat''. Another example of informal usage is the term '' heat content'', used despite the fact that p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Energy
Electrical energy is energy related to forces on electrically charged particles and the movement of electrically charged particles (often electrons in wires, but not always). This energy is supplied by the combination of electric current and electric potential (often referred to as voltage because electric potential is measured in volts) that is delivered by an electrical circuit (e.g., provided by an electric power utility). Motion (current) is not required; for example, if there is a voltage difference in combination with charged particles, such as static electricity or a charged capacitor, the moving electrical energy is typically converted to another form of energy (e.g., thermal, motion, sound, light, radio waves, etc.). Electrical energy is usually sold by the kilowatt hour (1 kW·h = 3.6 MJ) which is the product of the power in kilowatts multiplied by running time in hours. Electric utilities measure energy using an electricity meter, which keeps a running total of the elec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Current Source
A current source is an electronic circuit that delivers or absorbs an electric current which is independent of the voltage across it. A current source is the dual of a voltage source. The term ''current sink'' is sometimes used for sources fed from a negative voltage supply. Figure 1 shows the schematic symbol for an ideal current source driving a resistive load. There are two types. An ''independent current source'' (or sink) delivers a constant current. A ''dependent current source'' delivers a current which is proportional to some other voltage or current in the circuit. Background , - align="center" , style="padding: 1em 2em 0;", , style="padding: 1em 2em 0;", , - align="center" , Voltage source , Current source , - align="center" , style="padding: 1em 2em 0;", , style="padding: 1em 2em 0;", , - align="center" , Controlled voltage source , Controlled current source , - align="center" , style="padding: 1em 2em 0;", , style="padding: 1em 2em 0;", , - align ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ZS Lasten 01 Klein
ZS, Zs, zS, or zs may refer to: Businesses and organizations * Azzurra Air (IATA airline designator ZS) * Zombie Squad, a disaster preparedness group * ZS Associates, a consulting firm * Greens of Serbia (''Zeleni Srbije''), a political party in Serbia * Healthy Serbia (''Zdrava Srbija''), a political party in Serbia Places * American Samoa (World Meteorological Organization country code ZS) * Szczecin, a city in Poland identified by the vehicle registration code ''ZS'' Science and technology * Zeptosecond, a unit of time equal to 10−21 seconds * Zeptosiemens, an SI unit of electric conductance * Zettasiemens, an SI unit of electric conductance * Zettasecond, a unit of time equal to 1021 seconds * Zs, the category for "Separator, Space" characters in the Unicode standard Other uses * Zs (band), a musical group from Brooklyn, New York, United States * Hungarian zs, the last (forty-fourth) letter of the Hungarian alphabet, following z * MG ZS The MG ZS is an automobile nameplate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Load Bank
A load bank is a piece of electrical test equipment used to simulate an electrical load, to test an electric power source without connecting it to its normal operating load. During testing, adjustment, calibration, or verification procedures, a load bank is connected to the output of a power source, such as an electric generator, battery, servoamplifier or photovoltaic system, in place of its usual load. The load bank presents the source with electrical characteristics similar to its standard operating load, while dissipating the power output that would normally be consumed by it. The power is usually converted to heat by a heavy duty resistor or bank of resistive heating elements in the device, and the heat removed by a forced air or water cooling system. The device usually also includes instruments for metering, load control, and overload protection. Load banks can either be permanently installed at a facility to be connected to a power source when needed, or portable ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-linear
In mathematics and science, a nonlinear system is a system in which the change of the output is not proportional to the change of the input. Nonlinear problems are of interest to engineers, biologists, physicists, mathematicians, and many other scientists because most systems are inherently nonlinear in nature. Nonlinear dynamical systems, describing changes in variables over time, may appear chaotic, unpredictable, or counterintuitive, contrasting with much simpler linear systems. Typically, the behavior of a nonlinear system is described in mathematics by a nonlinear system of equations, which is a set of simultaneous equations in which the unknowns (or the unknown functions in the case of differential equations) appear as variables of a polynomial of degree higher than one or in the argument of a function which is not a polynomial of degree one. In other words, in a nonlinear system of equations, the equation(s) to be solved cannot be written as a linear combination of the un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reaction (physics)
As described by the third of Newton's laws of motion of classical mechanics, all forces occur in pairs such that if one object exerts a force on another object, then the second object exerts an equal and opposite reaction force on the first. The third law is also more generally stated as: "To every action there is always opposed an equal reaction: or the mutual actions of two bodies upon each other are always equal, and directed to contrary parts."This translation of the third law and the commentary following it can be found in the " Principia" opage 20 of volume 1 of the 1729 translation The attribution of which of the two forces is the action and which is the reaction is arbitrary. Either of the two can be considered the action, while the other is its associated reaction. Examples Interaction with ground When something is exerting force on the ground, the ground will push back with equal force in the opposite direction. In certain fields of applied physics, such as biomechanics, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voice Coil
A voice coil (consisting of a former, collar, and winding) is the coil of wire attached to the apex of a loudspeaker cone. It provides the motive force to the cone by the reaction of a magnetic field to the current passing through it. The term is also used for voice coil linear motors, such as those used to move the heads inside hard disk drives, which produce a larger force and move a longer distance but work on the same principle. Operation By driving a current through the voice coil, a magnetic field is produced. This magnetic field causes the voice coil to react to the magnetic field from a permanent magnet fixed to the speaker's frame, thereby moving the cone of the speaker. By applying an audio waveform to the voice coil, the cone will reproduce the sound pressure waves, corresponding to the original input signal. Design considerations Because the moving parts of the speaker must be of low mass (to accurately reproduce high-frequency sounds without being damped too much ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Audio Amplifier
An audio power amplifier (or power amp) is an electronic amplifier that amplifies low-power electronic audio signals, such as the signal from a radio receiver or an electric guitar pickup, to a level that is high enough for driving loudspeakers or headphones. Audio power amplifiers are found in all manner of sound systems including sound reinforcement, public address and home audio systems and musical instrument amplifiers like guitar amplifiers. It is the final electronic stage in a typical audio playback chain before the signal is sent to the loudspeakers. The preceding stages in such a chain are low power audio amplifiers which perform tasks like pre-amplification of the signal (this is particularly associated with record turntable signals, microphone signals and electric instrument signals from pickups, such as the electric guitar and electric bass), equalization (e.g., adjusting the bass and treble), tone controls, mixing different input signals or adding electro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Resistor Loads For Amplifier Test
A resistor is a passive two-terminal electrical 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. Resistor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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