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Culture / Music

Basics of electroacoustics

Understand the basics of sound reproduction.

Found 85 items

Logic gates and other digital electronic devices produced in the composition series of chips. The series of chips is a collection of circuits, characterized by shared technological and circuit solutions, as well as levels of the electrical signals and the supply voltage. The above classification covers not only the logical elements, and other digital devices, including microprocessor. However, it should be noted that the production of complex digital devices, some logic is not used and not used. We give examples of series circuits: TTL of K155, KM155, K133, KM133; hook up 530, KR531, KM531, K1531, 533, K555, KM555, 1533, KR1533; read more

To increase the operation speed of elements TTL uses transistors with a Schottky diode (Schottky transistors). The switching speed of the transistor is mainly determined by the decay time of accumulated charges. To increase the maximum switching frequency is necessary to prevent saturation of the transistor. Due to this charge accumulation is eliminated. read more

A Characteristic feature of the TTL output stage are MOSFETs. These transistors are designed in such a way that do not impact on each other. Each emitter has a corresponding p-n junction. In the first approximation output stage transistor can be modeled by the diagram on the diode (the dotted line in Fig. 18.8), in this case it works like the diagram of diode-transistor logic. read more

Currently, with the development of integrated circuits (IC) is the most widely following types of logic elements: – transistor-transistor logic (TTL); – transistor-transistor logic with Schottky diodes (hook up); – emitter-connected logic (ECL); – integrated-injection logic (I2L); – logic on complementary field-effect transistors (CMOS). The most common today are the IP that implement TTL and its variants. Integrated circuits of this type have an average performance and average power consumption. read more

Until now, essentially schematic, input and output voltages which vary within a certain range of values: R C-chain, integrators, rectifiers, amplifiers, etc. It is natural, when the signals which have to deal with, or are of a continuing nature (e.g., sound) or represent a continuously varying voltage coming from the measuring devices (e.g., devices to measure temperature or detect light radiation, biological or chemical probes, etc.). read more

Pulse isn have compared to the linear number of advantages. Their efficiency is much higher, as through the use of key mode of operation of the regulating transistor, the average power dissipation for this power is significantly lower than in the linear regulator. Small heat losses allow in many cases to abandon the use of heat sinks or significantly reduce their size. In addition, along with the usual mode of lowering the input voltage, the pulse isn can operate in the mode of its increase in the middle. Consider the principle of reducing, raising and inverting of voltage stabilizers, simplified structural diagram of the power unit which is shown respectively in Fig. 17.10 a, b, read more

The Output voltage at the output of the filter typically has a significant ripple because the capacitors can not be chosen infinitely large. In addition, the output voltage of such schemes strongly depends on the voltage fluctuations and load changes. To reduce the influence of these factors typically use voltage stabilizers. read more

The secondary power supply Sources (IWEP) are converters of electrical energy, receiving it from the primary voltage is AC or DC, galvanic cells, solar batteries. These devices transform the input energy by the nature of the current, values of current and voltage, if necessary, adjusting or stabilizing them. Common IWEP called power sources. read more

Generators with quartz resonators (usually referred to simply as quartz oscillators) are used when it is necessary to obtain stable oscillation frequency. A quartz crystal resonator is high-q filter, the frequency properties of which are determined by the geometrical dimensions and the type of vibration of a plate. The use of quartz resonators allows to provide a relative frequency variation not exceeding 10-6 – 10-9, which is several orders of magnitude better than the relevant parameters of the LC - and RC-oscillators. read more

Electrical processes in the multivibrators transistors, operational amplifiers, logic elements, similar. Structurally they are also built schemes: 2 transistors in the circuit of OE or 2LE with the denial of types AND-NOT, OR-NOT included in series. The multivibrator has two temporarily stable States: one LE (chip) is closed, the other open and Vice versa. Options time-setting RC-circuits determine the frequency of the multivibrator. read more

In the electronic technology widely used device, the shape of the output voltage which differs from a sine wave. These oscillations are called relaxation, a multivibrator is a type of one of the relaxation generators. The flop (from the Latin words multim – lot and vibro – oscillation) relaxation generator of pulses of rectangular shape, made in the form of the reinforcing device with the chain of positive feedback (PIC). The pulse generators can operate in one of three modes: self-oscillating waiting or synchronization. read more

Conditions for the occurrence of oscillations. Positive feedback is the main feature of all generators. Refer to the block diagram of generator with positive feedback (Fig.16.1). This scheme is similar to the corresponding block diagram of the amplifier with feedback. When considering feedback amplifiers, it was determined that the gain of any feedback amplifier is given by: OS= / (1 ± ), (16.1) read more

A Generator of electrical oscillations is called a device that converts the energy of the power source DC voltage in the energy variable of oscillations of the desired shape. Depending on the shape of the output voltage are distinguished: generators harmonic generators harmonic oscillations (pulse generators). Any generator, regardless of the shape of the output oscillations can operate in one of two modes: self-oscillation mode and external trigger mode (standby). Generator operating in the mode of self-oscillations is usually called the oscillator. Output AC voltage at its output is formed immediately after connecting the supply voltage and does not require to start the operation of feeding external control action. read more

Draw the digital switch circuit based on MOS-transistor with induced channel, drain of the resistor R and timing diagrams of its operation (Fig.15.14). The diagram shows the load capacity With modeling the capacity of devices connected to the transistor key. It is obvious that with zero input signal, the transistor is turned off and U And C = E P. If the voltage U Z more thresholds U Z THEN transistor, then it opens and the voltage U C decreases to a residual voltage U on. read more

Keys on field-effect transistors are used for switching both analog and digital signals. Advantages of the keys on field-effect transistors are: - small residual stress on the lever in the open position; - high resistance in nonconducting condition and, as a result, a small current flowing through the transistor, the channel of which is blocked; - low power consumption from the source of control voltage; - good electrical isolation between the control circuit and the circuit with the switching signal; - possibility of switching of electrical signals is very low (of the order of µv). read more