Power Supplies.
Most electronic devices require DC voltages for operation. These tensions can be supplied by batteries or internal power supplies that convert alternating current, which can be obtained from the electrical network that reaches every home in regulated DC voltages. The first element of a DC power source inside the transformer, which raises or lowers the input voltage to a level suitable for operating the equipment. The transformer secondary function is to serve as mass insulation (ground) electrical device to reduce potential dangers of electrocution. Here lies a transformer rectifier, usually a diode. In the past, using vacuum diodes and a wide variety of different materials (crystals of germanium or cadmium sulfate) in low-power rectifiers used in electronic equipment. It is now used almost exclusively silicon rectifiers because of their low cost and high reliability.
fluctuations and undulations superimposed to the rectified DC voltage (perceived as a ringing in the defective amplifiers) can be filtered by a capacitor. The larger the capacitor, the lower the level of voltage fluctuation. It is possible to achieve a more precise control over levels and voltage fluctuations with a voltage regulator, which also ensures that the internal stresses are independent of fluctuations that may be in an electrical appliance. A simple voltage regulator that is often used is the Zener diode, formed by a pn junction diode solid-state acts as an insulator to a predetermined tension. Above this voltage, becomes a driver excess voltage drift. In general, the more sophisticated voltage regulators are built as integrated circuits.
amplifier circuits
electronic amplifiers are used all to increase the voltage, current or power of a signal. Linear amplifiers increase the signal without distortion (or minimally distorting it), so that the output is proportional to the input. Nonlinear amplifiers can generate a significant change in the waveform of the signal. Linear amplifiers are used for audio and video signals, while used in nonlinear oscillators, power electronic devices, modulators, mixers, logic circuits and other applications that require a reduction in amplitude. Although vacuum tubes were very important in amplifiers, today commonly used discrete transistor circuits or integrated circuits.
Sound Amplifiers
sound amplifiers, commonly used in radios, televisions and recorders tapes, typically operate at frequencies between 2 and 20 kiloherz (1 kHz = 1,000 cycles per second). Amplify the electrical signal, then sound becomes a speaker. Operational amplifiers, built-in integrated circuits and linear amplifiers consist of multiphase dc-coupled, are very popular as amplifiers.
video amplifiers
video amplifiers primarily used for signals with a frequency range up to 6 megahertz (1 MHz = 1 million cycles per second). The signal generated by the amplifier becomes the visual information such as the one shown on the television screen, and controls the signal amplitude the brightness of the points that form the image. To perform this function, a video amplifier must operate in a broadband and equally amplify all signals with low distortion.
RF Amplifiers
These Amplifiers increase the signal level communication systems GHz = 1,000 million cycles per second) and can reach even the microwave frequency range.
oscillators
oscillators consist of an amplifier and some sort of feedback loop: the output is redirected to the amplifier input. The determinants of the frequency can be an inductance-capacitance circuit or a crystal vibrator tuned. Crystal controlled oscillators provide greater accuracy and stability. The oscillators are used to produce sound signals and radio in a wide variety of applications. For example, simple radio frequency oscillators are used in modern telephones to transmit key data to the central telephone station to dial a number. Ring tones generated by the oscillators are also found in alarm clocks, radios, electronic instruments, computers and alarm systems. High frequency oscillators are used in communications equipment to control the tuning functions and signal detection. Radio stations and television use high-frequency oscillators and high precision to generate the airwaves.
Logic Circuits
The switching and timing circuits, or logic circuits form the basis of any device that will have to select or combine signals from controlled manner. Among the application fields of these types of circuits may be mentioned the telephone switching, satellite broadcasting and operation of digital computers.
digital logic is a rational process to adopt simple decision of "true" or 'false' based on the rules of Boolean algebra. The true state is represented by a 1 and false by 0, and logic circuits these numerals appear as signals of two different voltages. Logic circuits are used to make specific decisions 'true-false' on the basis of the presence of multiple signals 'true-false' in the entries. The signals can be generated by mechanical switches or solid state transducers. The input signal, once accepted and conditioned (to remove unwanted electrical signals or noise), is processed by digital logic circuits. The various families of digital logic devices, usually integrated circuits, perform a variety of logic functions through call gates, as the gates OR, AND, NOT and combinations thereof (such as 'NOR', which includes OR and NOT). Another widely used logic family is transistor-transistor logic. It is also used logic complementary metal oxide semiconductor, that performs similar to very low power levels but slightly lower operating speeds. There are also many other varieties of logic circuits, including the now obsolete resistor-transistor logic and emitter coupled logic, used for very high speed systems.
The building blocks of a logical device called digital logic gates. AND gate (AND) has two or more inputs and one output. The output of an AND gate is true only if all inputs are true. An OR gate (OR) has two or more inputs and one output. The output of an OR gate is true if either input is true, and false if all inputs are false. A door INVERSORA (INVERTER) is a single input and single output, and can convert a real signal in false, thus making the function negation (NOT). Based on the basic gates can build more complex logic circuits, among which may be mentioned bistable circuits (also called flip-flops, which are binary switches), counters, comparators, adders and more complex combinations.
In general, to perform a certain function is necessary to connect large numbers of logic elements in complex circuits. In some cases using microprocessors to perform many of the functions of switching and timing of individual logic elements. The processors are specifically programmed with individual instructions to perform a certain task or tasks. One of the advantages of microprocessors is that they allow different logic functions depending on programming instructions stored. The disadvantage of microprocessors is that normally function in a sequential manner, which might be too slow for some applications. In such cases, use specially designed logic circuits.
Recent advances
The development of integrated circuits has revolutionized the fields of communications, information management and information technology. Integrated circuits have reduced the size of the devices with the consequent lower manufacturing costs and maintenance of systems. At the same time, offer greater speed and reliability. Digital watches, laptop computers and electronic games are microprocessor-based systems. Another important development is the digitization of audio signals, a process in which the frequency and amplitude of a sound signal is encoded digitally using proper sampling techniques, ie techniques to measure the amplitude of the signal at very short intervals . The digitally recorded music, including compact discs, is characterized by a fidelity it was not possible to achieve with direct recording methods.
medical electronics to come up with systems that can further differentiate the human body organs. They have also developed devices that allow viewing the blood vessels and respiratory system. HD also promises to replace many photographic processes by eliminating the need for silver.
Current research aimed at increasing speed and capacity of computers is mainly focused on improving circuit technology integrated components in the development of even faster switching. They have built large scale integrated circuits containing hundreds of thousands of components on a single chip. Have come to make computers that reach very high speeds at which semiconductors are replaced by superconducting circuits using Josephson junctions that operate at temperatures near absolute zero.
CRF
Lenny Z. Perez M
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