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Computer Power Supply
A power supply unit (PSU) converts Mains electricity, mains AC to low-voltage regulated DC power for the internal components of a computer. Modern personal computers universally use switched-mode power supply, switched-mode power supplies. Some Power supply, power supplies have a manual switch for selecting input voltage, while others automatically adapt to the mains voltage. Most modern desktop personal computer power supplies conform to the ATX, ATX specification, which includes form factor and voltage tolerances. While an ATX power supply is connected to the mains supply, it always provides a 5-volt standby (5VSB) power so that the standby functions on the computer and certain peripherals are powered. ATX power supplies are turned on and off by a signal from the motherboard. They also provide a signal to the motherboard to indicate when the DC voltages are in spec, so that the computer is able to safely power up and boot. The most recent ATX PSU standard is version 3.0 as of mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commodore PET
The Commodore PET is a line of personal computers produced starting in 1977 by Commodore International. A single all-in-one case combines a MOS Technology 6502 microprocessor, Commodore BASIC in read-only memory, keyboard, monochrome monitor, and, in early models, a cassette deck. Development of the system began in 1976, and a prototype was demonstrated at the January 1977 Consumer Electronics Show. The name "PET" was suggested by Andre Souson after he saw the Pet Rock in Los Gatos, and stated they were going to make the "pet computer". It was backronymed to Personal Electronic Transactor. A series of problems delayed production versions until December 1977, by which time the TRS-80 and Apple II had already begun deliveries. ''Byte'' referred to the three machines collectively as the "1977 trinity". Following the initial PET 2001, the design was updated through a series of models with more memory, better keyboard, larger screen, and other modifications. The systems were a top ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temperature Coefficient
A temperature coefficient describes the relative change of a physical property that is associated with a given change in temperature. For a property ''R'' that changes when the temperature changes by ''dT'', the temperature coefficient α is defined by the following equation: :\frac = \alpha\,dT Here α has the dimension of an inverse temperature and can be expressed e.g. in 1/K or K−1. If the temperature coefficient itself does not vary too much with temperature and \alpha\Delta T \ll 1, a linear approximation will be useful in estimating the value ''R'' of a property at a temperature ''T'', given its value ''R''0 at a reference temperature ''T''0: :R(T) = R(T_0)(1 + \alpha\Delta T), where Δ''T'' is the difference between ''T'' and ''T''0. For strongly temperature-dependent α, this approximation is only useful for small temperature differences Δ''T''. Temperature coefficients are specified for various applications, including electric and magnetic properties of materials a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power-factor Correction
In electrical engineering, the power factor of an AC power system is defined as the ratio of the '' real power'' absorbed by the load to the ''apparent power'' flowing in the circuit. Real power is the average of the instantaneous product of voltage and current and represents the capacity of the electricity for performing work. Apparent power is the product of RMS current and voltage. Due to energy stored in the load and returned to the source, or due to a non-linear load that distorts the wave shape of the current drawn from the source, the apparent power may be greater than the real power, so more current flows in the circuit than would be required to transfer real power alone. A power factor magnitude of less than one indicates the voltage and current are not in phase, reducing the average product of the two. A negative power factor occurs when the device (which is normally the load) generates real power, which then flows back towards the source. In an electric power system ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Varistor
A varistor is an electronic component with an electrical resistance that varies with the applied voltage. Also known as a voltage-dependent resistor (VDR), it has a nonlinear, non- ohmic current–voltage characteristic that is similar to that of a diode. Unlike a diode however, it has the same characteristic for both directions of traversing current. Traditionally, varistors were indeed constructed by connecting two rectifiers, such as the copper-oxide or germanium-oxide rectifier in antiparallel configuration. At low voltage the varistor has a high electrical resistance which decreases as the voltage is raised. Modern varistors are primarily based on sintered ceramic metal-oxide materials which exhibit directional behavior only on a microscopic scale. This type is commonly known as the metal-oxide varistor (MOV). Varistors are used as control or compensation elements in circuits either to provide optimal operating conditions or to protect against excessive transient voltages ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bleeder Resistor
In electronics, a bleeder resistor, bleeder load, leakage resistor, capacitor discharge resistor or safety discharge resistor is a resistor connected in parallel circuit, parallel with the output of a high-voltage power supply circuit for the purpose of discharging the electric charge stored in the power supply's filter capacitors when the equipment is turned off, for safety reasons. It eliminates the possibility of a leftover charge causing electric shock if people handle or service the equipment in the off state, believing it is safe. A bleeder resistor is usually a standard resistor rather than a specialized component. Usage DC power supplies The power supply circuits in electronic equipment that produce direct current (DC) needed by the device from the alternating current (AC) supplied by mains power, mains use filter capacitors to smoothing capacitor, smooth the DC current. A large electric charge can remain in these capacitors after the unit is turned off, constituting a sho ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Filter Capacitor
Capacitors have many uses in electronic and electrical systems. They are so ubiquitous that it is rare that an electrical product does not include at least one for some purpose. Energy storage A capacitor can store electric energy when it is connected to its charging circuit and when it is disconnected from its charging circuit, it can dissipate that stored energy, so it can be used like a temporary battery. Capacitors are commonly used in electronic devices to maintain power supply while batteries are being changed. (This prevents loss of information in volatile memory.) Conventional electrostatic capacitors provide less than 360 joules per kilogram of energy density, while capacitors using developing technology can provide more than 2.52 kilo joules per kilogram. In car audio systems, large capacitors store energy for the amplifier to use on demand. An uninterruptible power supply (UPS) can be equipped with maintenance-free capacitors to extend service life. Pulsed powe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delon Circuit
A voltage doubler is an electronic circuit which charges capacitors from the input voltage and switches these charges in such a way that, in the ideal case, exactly twice the voltage is produced at the output as at its input. The simplest of these circuits are a form of rectifier which take an AC voltage as input and outputs a doubled DC voltage. The switching elements are simple diodes and they are driven to switch state merely by the alternating voltage of the input. DC-to-DC voltage doublers cannot switch in this way and require a driving circuit to control the switching. They frequently also require a switching element that can be controlled directly, such as a transistor, rather than relying on the voltage across the switch as in the simple AC-to-DC case. Voltage doublers are a variety of voltage multiplier circuit. Many, but not all, voltage doubler circuits can be viewed as a single stage of a higher order multiplier: cascading identical stages together achieves a great ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rod Holt
Frederick Rodney Holt Moritz, Michael, ''The Little Kingdom,'' ebook (born 1934) is an American computer engineer and political activist. He is Apple employee #5, and developed the unique power supply for the 1977 Apple II. Actor Ron Eldard portrayed him in the 2013 film, ''Jobs.'' Background Holt was born in 1934 to a psychiatry resident father and artist and teacher mother. He became interested in electronics by the age of 14 and taught ham radio courses for Wellesley High School by the age of 16. In 1952, after graduating from high school, Holt married his high school girlfriend Joanne. He also joined Ohio State University as a math major. He and Joanne had two children, Christine and Cheryl, during this period. Holt later stated that while at OSU, he also "became entranced with motorcycles and opened up my own motorcycle shop. That adventure failed within a year, however, and I then worked in the electronics industry to support my family. I continued to race bikes intermitt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atari
Atari () is a brand name that has been owned by several entities since its inception in 1972. It is currently owned by French publisher Atari SA through a subsidiary named Atari Interactive. The original Atari, Inc. (1972–1992), Atari, Inc., founded in Sunnyvale, California, in 1972 by Nolan Bushnell and Ted Dabney, was a pioneer in arcade games, home video game consoles and home computers. The company's products, such as ''Pong'' and the Atari 2600, helped define the electronic entertainment industry from the 1970s to the mid-1980s. In 1984, as a result of the video game crash of 1983, the home console and computer divisions of the original Atari Inc. were sold off, and the company was renamed Atari Games, Atari Games Inc. Atari Games received the rights to use the logo and brand name with appended text "Games" on arcade games, as well as the derivative coin-operated arcade rights to the original 1972–1984 arcade hardware properties. The Atari Consumer Electronics Division ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
