Author: John Mulindi
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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…
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The Principle of Operation of an Induction Potentiometer
An induction potentiometer is a rotary type linear-variable inductor with two concentrated windings wound on the stator and on the rotor as illustrated in the figure below: The rotor windings are excited with an AC, inducing voltage in the stator windings. The amplitude of the output is dependent on mutual inductance between the two coils,…
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Programmable Automation Controllers (PACs) – Features & Applications
What are Programmable Automation Controllers? Programmable automation controllers (PACs) are process controllers with an open configuration and possessing the enterprise integration power of a PC-based structure. In other words, PACs are industrial controllers that combine the functionality of a programmable logic controller (PLC) with the processing capability of a PC. Basic Features of Programmable Automation…
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The Principle of Operation of a Digital Frequency Meter
A frequency meter/counter is a digital instrument that can measure and display the frequency of any periodic waveform. Its operation is based on the principle of gating the unknown input signal into the counter for a predetermined time. For instance, if the unknown input signal were gated into the counter for exactly 1 second, the…
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The Role Played By Edge Computing in Manufacturing
Edge computing can be defined as a distributed computing framework that brings enterprise applications closer to data sources like local edge servers. In manufacturing, edge computing offers an effective processing and storage choice since intensive data handling and storage can be kept on the plant floor. Edge computing has developed, and plays an important role…
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How to Wire an Industrial Control Motor
Option 1: With a Toggle Switch Let’s consider a simple three-phase, 480V AC motor control circuit consisting of a contactor, overload block, control power transformer, power fuses or (you may use circuit breakers) and the associated components as illustrated in the figures below: The schematic diagram for the same circuit is shown below: The control…
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Schottky Diode – Features & Applications
Schottky diode is fabricated as a metal-to-N junction rather than a P-N semiconductor junction. Also referred to as hot-carrier diodes, Schottky diodes are characterized by fast switching times (low reverse-recovery time), low forward voltage drop (normally 0.25 to 0.4 volts for a metal-silicon junction), and low junction capacitance. The forward voltage drop (VF), reverse-recovery time…
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Basic Features of Cascade Control
A cascade control system typically consists of a primary or master controller that generates a control function that serves as the setpoint for a secondary or slave controller. That controller in turn utilizes the actuator to apply its control function directly to the secondary process. The secondary process then generates a secondary process variable that…
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Combustion & Temperature Control for a Direct-Fired Process Heater
The figure below shows the control schemes applied to a direct-fired process heater. From the diagram above, the heat from the burning fuel is applied directly to the tubes carrying the process fluid in similar way as the water tubes in a steam generator. This type of heater is usually used as a reboiler in…