Author: John Mulindi
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Ideal Transformers
A transformer consists of several coils wound on a common core that usually consists of laminated iron (to reduce eddy-current loss). Transformers are usually used to adjust the values of ac voltages. A transformer can step up or step down voltage. Transformers are used in electric power distribution. To transport power over long distance, large…
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Proportional Control Systems
The control mode In the proportional control mode, the final control element is throttled to various positions that are dependent on the process systems conditions. The controller operates within a band that is between the 0 % output point and the 100 % output point and where the output of the controller is proportional to…
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Components that make up a RF Communication System
Communication is the process of transferring information from one place to another. The information that is generated at the source is transferred to the receiver through communication channel. From the diagram above, on the source side, there is a transmitter device that makes the input electrical information suitable for efficient transmission over a given channel.…
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Modes of Automatic Control
The mode of control can be defined as the way or manner in which a control system makes corrections relative to an error that exists between the desired value (setpoint) of a controlled variable and its actual value. Any particular mode of control used for a specific application depends on the characteristic of the process…
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Resistance and Resistivity
The resistance of an electrical conductor depends on 4 factors, namely: The resistance, R, is directly proportional to length L of a conductor. Resistance, R, is inversely proportional to cross-sectional area a, of a conductor. Because R is proportional to L and, R is proportional to By inserting a constant of proportionality into this relationship,…
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Transformers
A transformer is a device used to change the relative amplitudes of voltages and current in an AC circuit. A transformer consists of primary and secondary windings whose magnetic fluxes are linked by a ferromagnetic core. The principle of working of a transformer is based on the fact that two coils that are wound on…
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Two Position Controller
A Two position controller is a device that has two operating conditions: Completely ON or completely OFF. From the figure above, we can see the characteristic waveform for a two position controller that switches from its ‘’OFF’’ state to ‘’ON’’ state when the measured variable increases above the setpoint. Conversely, it switches from its ‘’ON’’…
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Electromagnetism and Its Applications
What is Magnetism? Magnetism is the force exerted by magnets when they attract or repel each other. This magnetism force is caused by the motion of electric charges. Every element or substance is made up of tiny units called atoms. Each atom has electrons (particles that carry electric charges). The electron spins around the nucleus…
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Process Time Lags and Stability of Automatic Control Systems
Processes have the characteristics of delaying and retarding changes in the values of the process variables. Process time lags generally describe these process delays and retardations. Process time lags are caused by three properties of the process. They include: Capacitance Resistance Transportation time Capacitance is the ability of a process to store energy. This energy-storing…