Electronic throttle - is a specialized, used in a professional environment, a slang designation simplest solid stabilizers.
It is difficult to say who came up with this strange name, but it is occasionally used by radio amateurs.
Parametric stabilizers - electronic throttles
The idea of using stabilizers instead of filters is based not on an empty place. The bottom line is you want to learn how to filter the noise until the desired signal passes freely. It is known that the throttle well lets low frequencies. This is the basis of its use as a filter in the recording and playing tunes. Ear audible frequency detected in the upper limit of 15 kHz, although some people hear up to 20 kHz. If the report vibrations of the skull bones, hearing limits apply up to 220 kHz. It is alleged that the person through the fillings in your teeth is capable of receiving broadcasts in the ultra-low range. But let us for the special services of their game with the mind and return to the record.
Chokes are used to cut off frequencies above 20 kHz. They have set speakers to remove known radio amateurs of "white noise". Simple people call the sound of hissing, it intrusive, easily recognizable even against the background of loud music. Music fans started to think how to get rid of the scourge. Among them are amateur radio, and someone suggested using the amplitude-frequency (transfer) of the cascade function for cutting the "white noise". The effect is based on the fact that more than 20 kHz of the desired signal is not present, and there is a significant part of the spectrum hiss.
We tried to do, and immediately noted partial improvement. Technology set in motion, the only drawback were the big choke size. A legend walking among music fans - and the authors personally heard - that electronic units are not expected to solid state electronics (transistors, thyristors and so on.). Even diodes use undesirable. Therefore, people do not agree to use parametric stabilizers in hardware. But the big choke size makes it necessary to replace it with electronics.
Briefly on Conventional chokes
Choke inductor is similar, but shows a specific purpose and number of windings. Without going into the subject say that the proposed roll wire spiral Laplace, then the action did Shveygger, Ampere, Faraday and other scientists. Thus was born, probably in 1820 there was an inductor.
The key property is not immediately detected, was the presence of the reactance. It was called - inductance. Feature: current in such element is not able to rise immediately, then it is cut off and smoothed edge becomes steep. This corresponds to the spectrum at low pass filtering that is used to reduce power music lovers hiss.
The column typically includes a number of speakers. For example, three. And hisses the smallest for reproducing high frequencies, for example, a thin violin singing. If you carefully cover the speaker with his hand, "white noise" disappears. This is akin to mechanical filtration using hands.
Scheme electronic throttle
We want to thank Eugene Karpov. Anyone has the right to read them lined paper "Electronic throttle", for a discussion of the major mistakes on the construction equipment, provides advice on improvement of quality.
Inclusion of the common-base circuit is called comparative. Transistor evaluates the difference of stress at the base and collector. Signal is taken from the emitter. Capacitor C3 is charged through resistor R5 serving parametric stabilizer (instead of the zener diode). Unusual solution required to track relatively slowly varying audible signal. The capacitor is invariably its averaged value, since there is a stabilization. Transistor ensures that the output signal is (or remained proportional) voltage on the stabilizer.
Thus a simple scheme briefly operates electronic throttle. The reason for using partially disclosed Evgeny Karpov, but it is not obvious to ordinary citizens. Choke big and heavy, take up much space, making addition insalubrious two things:
- It brings a considerable ohmic circuit (active) resistance in Ohm's law applied to the chain section.
- Has an inductive impedance shifts the phase between current and voltage. Experts are inclined to consider it a defect.
Electronic throttle allows you to remove these shortcomings, but Yevgeny Karpov notes that the size of the heat sink for the transistor is significant that destroys advantage. And the need for fine-tuning is not everyone's strength. However, electronic ballasts have the right to be used as a representative of the simplest forms of parametric stabilizers.
Rationale for the electronic throttle
It is believed that the stabilizer task is to stabilize the voltage, ensuring constancy. In fact, it usually comes to the current value. The stabilizer is arranged to pass slow components. Acceptable adding feedback voltage standards to eliminate this "deficiency".
Hams intentionally missing electronic throttle structure similar navoroty obtained device safely floats along the relevant frequencies. At the exit there is a filter of the capacitor C4, resistors set the operating point of the transistor.
In a global sense, voltage regulators are divided into two classes:
The first is usually based on a certain standard. For example, a simple parametric stabilizer becomes a single zener diode. But it is impossible to achieve a high output voltage and current will be shared, is wasted. High losses, the need for cooling... It tried to overcome compensated stabilizers, where the chain laid feedback. Meaning: not compare with the standard input voltage and the output and "test" results to conduct an adjustment factor of the amplifier stage.
Electronic throttle intentionally made without feedback parameters to float and not interfere with the desired signal to pass to the output. Electronic throttle is not parametric stabilizer directly, but is deliberately degraded variant. Deteriorated in terms of stability. The output characteristics of the ideal is considered straight, do not mean music. Output:
Electronic throttle - a parametric voltage stabilizer with intentionally impaired long-term characteristics providing gradual voltage care in the right direction according to the shape of the input signal.
The simplest scheme stabilizers
Cited above simplistic interpretation of the question - forgive us real hams. In fact, electronic ballasts using a cascade of comparison of the compensation regulator. And the easiest available, of a single transistor. We briefly theory.
So simple parametric stabilizer becomes a kind of solid-state diode - Zener. When exceeding a certain threshold voltage is a sharp drop in resistivity p-n-junction. Zener, contrary to the conventional diode forward current is always included. The cathode ntrebuetsya file plus. threshold value is easily changed between the switching circuit and Zener diodes neutral in the forward direction. Each silicon p-n-transition falls 0.5 V. It is sometimes taken for temperature compensation.
Complexity of the circuit is the transistor, which serves as the reference zener diode and triode has been stabilized. At the output of the emitter follower is turned for improved matching with a load, and the inclusion of the common base current stabilizes. But it's time to look at the scheme of compensatory stabilizers, where electronic throttle something took.
The figure shows the control elements of the component transistors. This stage, which is fed a feedback loop for comparison with the benchmark. One of the compared voltages is fed to emitter - by Zener, the second - on the base - from the feedback circuit. Since the collector signal is removed. Transistor considered symmetric, except for minor details described in the relevant subject (see. a bipolar transistor), it is permissible to use for comparison base and collector, as in the electronic throttle scheme given above.
Exception - feedback loop of the structure vykushena. But instead included a reference capacitor, certainly not outstanding DC voltage, delighting amateur radio. The time constant is taken such that the time to change the useful signal according to the frequency (20 kHz) and high frequencies smoothed. And while music lovers against solid-state electronics, the design has the right to exist.
For temperature compensation, and increasing the sensitivity may create several comparative elements of transistors and to achieve partial amplification. In particular, this is achieved by using a differential pair (see. operational amplifiers). Created other useful schemes, examples, readers will find yourself in an eye-opening book edited by GS Nayvelta.
It remains to add that the electronic throttle and going on field-effect transistor (MOSFET). Then stabilizing properties deteriorate, and the cascade adds the noise, which is struggling in the chain. Karpov adds that the electronic filter hardness is much more due to the stored energy in the capacitor is allowed to use at any time, and less resistance. Electronic throttle fine filters voltage of 50 Hz and is used in low-power power supplies. However, the noise suppressing device worse than traditional LC-band pass filter. Consequently, fed apparatus should not be critical to the level of noise.