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A Voltage controller thyristor based dimmer rack An electrical schematic for a typical SCR-based light dimmer. A voltage controller, also called an AC voltage controller or AC regulator is an electronic module based on either thyristors, triodes for alternating current, silicon-controlled rectifiers or insulated-gate bipolar transistors, which converts a fixed voltage, fixed frequency ...
HF's position in the electromagnetic spectrum.. High frequency (HF) is the ITU designation [1] [2] for the band of radio waves with frequency between 3 and 30 megahertz (MHz). It is also known as the decameter band or decameter wave as its wavelengths range from one to ten decameters (ten to one hundred meters).
Transformers, autotransformers, and baluns are sometimes incorporated into the design of narrow band antenna tuners and antenna cabling connections. They will all usually have little effect on the resonant frequency of either the antenna or the narrow band transmitter circuits, but can widen the range of impedances that the antenna tuner can match, and/or convert between balanced and ...
Long wires between the components may reduce the high-frequency filter efficiency provided by the capacitors at the inlet and outlet. Stable switching frequency may be important. Electronic noise at the output terminals: Linear regulators generally have excellent rejection of AC line ripple and are generally lower noise than switched-mode ...
From the plot, it can be seen that for frequencies well below the corner frequency, the circuit has an attenuation of 0 dB, corresponding to a unity pass-band gain, i.e. the amplitude of the filter output equals the amplitude of the input. Frequencies above the corner frequency are attenuated – the higher the frequency, the higher the ...
The filtering requirements for such power supplies are much easier to meet owing to the high frequency of the ripple waveform. The ripple frequency in switch-mode power supplies is not related to the line frequency, but is instead a multiple of the frequency of the chopper circuit, which is usually in the range of 50 kHz to 1 MHz. [citation needed]
Thus the output is locked to the frequency at the other input. This other input is called the reference and is usually derived from a crystal oscillator, which is very stable in frequency. The block diagram below shows the basic elements and arrangement of a PLL based frequency synthesizer. Block diagram of a common type of PLL synthesizer.
Magnitude response of a low pass filter with 6 dB per octave or 20 dB per decade roll-off. Measuring the frequency response typically involves exciting the system with an input signal and measuring the resulting output signal, calculating the frequency spectra of the two signals (for example, using the fast Fourier transform for discrete signals), and comparing the spectra to isolate the ...