Author: John Mulindi
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Miniature Circuit Breakers (MCBs)
Miniature circuit breakers (MCBs) are electromechanical devices that protect an electrical circuit from over currents, in other words, MCBs are switches that automatically turns OFF when the current flowing them exceeds the maximum allowable limit. Over currents in an electrical circuit may be caused by short circuits overload or faulty designs. MCBs functions by interrupting…
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Overhead vs. Underground Power Distribution Systems
A power distribution system is the electrical system between the sub-station fed by the transmission system and the consumer’s meters. A distribution system generally is made up of feeders, distributors and the service mains. In this case, a feeder is a conductor which connects the substation (localized generating station) to the area where the power…
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Phase-Locked Loops (PLL) – Features, Operation & Applications
Features of a Phase-Locked Loop (PLL) A phase-locked loop (PLL) is a form of a servo system which consists of a phase detector, low-pass filter and voltage controlled-oscillator (VCO) as illustrated in the block diagram below. The phase detector compares the phase of the VCO with the incoming reference signal, giving an output proportional to…
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Voltage Doubler Circuit Operation
A voltage multiplier is a specialized rectifier circuit capable of producing dc output voltage which is theoretically an integer times the AC peak input, for instance, it is possible to get 200 VDC from a 100 Vpeak AC source using a voltage doubler, 300 VDC using a voltage tripler or 400 VDC using a voltage…
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Clamper Circuits – Features & Applications
A clamper circuit or dc restorer is used to clamp a peak of a waveform to a specific DC level compared with a capacitive coupled signal which swings about its average DC level (normally 0 V). If the diode is removed from the clamper, it defaults to a simple coupling capacitor – that is, no…
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Clipper Circuits – Features & Applications
A clipper also referred to as a limiter is a circuit which removes the peak of a waveform. A clipper consists of diodes, resistors and sometimes DC sources to clip or limit the output to a certain level. The input-output characteristics of clipper circuits are typically similar to those of the forward-biased and reverse-biased diode…
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Linear/Analog vs. Digital Integrated Circuits (ICs)
Linear ICs (LICs) also referred to as analog ICs are characterized by inputs and outputs that can take a continuous range of values. In addition, the outputs are generally proportional to the inputs. On the other hand, Digital ICs contain circuits whose input and output voltages are limited to two possible levels i.e. low or…
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Radio Frequency (RF) Signal Generator – Features & Applications
A radio frequency (RF) signal generator is used in generating high frequency signals at a specific frequency for testing laboratories. The output frequency may range for example from about 100 kHz to around 40 GHz. A typical RG generator consists of: RF oscillator, amplifier, output level meter and a calibrated attenuator. Components of RF Generator…
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PIN Diode – Features & Applications
PIN diode is characterized by fast low capacitance switching. A PIN diode is fabricated in a similar fashion to a silicon switching diode with an intrinsic region added between the PN junction layers. This generates a thicker depletion region, the insulating layer at the junction of a reverse biased diode. This results in lower capacitance…
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Diode & Filter Applications in Amplitude Modulation (AM) Detection Circuits
The operation of a typical AM audio frequency signal is illustrated in the Figure 1.0 where vin is the modulated signal that is shown Figure 1.1. A typical amplitude modulated signal that is fed into the detector circuit: The diode removes the lower envelope and the upper envelope is illustrated below: The capacitor C2 and…