Author: John Mulindi
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Analog Proportional Controller
An analog controller typically employs op-amps to provide the necessary gain and signal processing. Let’s consider the flow control system below: In the system above, the controller’s function is to maintain the flow of a liquid through a pipe at 6 gallons/minute. This system consists of: The flow valve is operated with a signal…
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Tuned Amplifier Applications
A tuned amplifier operates over a band of frequencies centered on a resonant frequency. Its two main requirements are to provide high gain and good selectivity. We have several applications in telecommunications systems where it is necessary to amplify a narrow band of frequencies centred on one frequency. A typical example is shown in the…
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Applications of Filters in Telecommunication Systems
Electronic filters have many applications in the telecommunication and data communications industry. For example, they are used in a multichannel communication system employing a technique known as time-division multiplexing (TDM). In this system, several channels are transmitted through a medium such as optical fiber or through a co-axial cable or waveguide. Multiplexing means combining several…
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How does diesel engine generate electricity?
What is power plant? A power plant is a facility that converts the energy of fuels into electricity. The term power plant is often used to refer to a coal-fired, nuclear, natural gas, or oil-fired electric generating station. Power plants are typically large industrial facilities that provide enough electricity to supply an industrial town or…
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Toggle Switches
Toggle switches are available in various contact configurations. Each switch consists of one or more poles, where each pole is actually a separate switch. The switch contact configurations include: Single-pole/single-throw switch (SPST) This is the simplest switch. It has a single set of contacts that can either open or close. Its contact configuration is illustrated…
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Electric Solenoid Actuator – Features & Operation
A typical electric solenoid actuator consists of a coil, armature, spring, and stem. This is illustrated in the figure below: The coil is connected to an external current supply. The spring rests on the armature to force it downward. The armature moves vertically inside the coil and transmits its motion through the stem to the…
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Pressure Control Valve Operation
A pressure control valve is a spring-loaded valve that is capable of maintaining a constant pressure in a system regardless of the flow rate. This is important, since most pumps e.g. gear pumps are constant-displacement types – a constant volume of fluid is pumped for each revolution of the pump shaft. If the pump were…
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Key Factors to Consider in Selection of Valves
Valves are the final element in a control loop, and are critical in providing the correct flow. The valve, usually operates in very harsh conditions, and is one of the most costly elements in the process control system. Their selection and correct installation require both knowledge and experience. Understanding system requirements and manufacturers specifications is…
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Features and Applications of Instrument Transformers
Instrument transformers are used in the measurement of voltage, current, energy, and power in ac circuits. The main reasons why instrument transformers are employed in measurements are: In power systems, the levels of currents and voltages handled are very high, and therefore direct measurements with conventional instruments is not possible without compromising the operator safety,…