Category: Electrical Circuits & Networks
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Types of Resistors
Resistors perform two basic functions in a circuit: they limit current flow and set voltage levels within a circuit. We have various kinds of resistors e.g. fixed resistors, variable resistors, digitally adjustable resistors, photoresistors, fusible resistors, etc. Generally, resistors can … Read more
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Alternating Currents and Voltages
Alternating current generator Let’s consider a signal turn coil rotating freely at a constant angular velocity symmetrically between the poles of a magnet as illustrated below: Figure 1(a) Simple single-loop ac generator The ends of the loop are terminated in … Read more
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AC Circuits with Resistors, Inductors and Capacitors
Purely Resistive Circuits In resistive elements the current and voltage are in phase. Figure 1(a) purely resistive circuit Figure 1(b) waveform of a purely resistive circuit (current in phase with voltage) Figure 1(c) phasor diagram resistive circuit Purely Capacitive Circuits… Read more
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DC Networks Theorems
The laws that determine the currents and voltage drops in DC networks: Ohm’s law The law’s for resistors in series and parallel networks Kirchhoff’s laws In addition to the above laws, we have several circuit theorems used to solve problems … Read more
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Key Facts about Resistors, Resistor Colour Codes and Resistor Tolerance
Resistors perform two basic functions in electronics: To limit current flow To set voltage levels within a circuit These two Resistor features of current limiting and voltage setting are implemented in various ways in electronics as listed below: Resistors are … Read more
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Inductance
What is Inductance? Inductance is the property of a circuit whereby there is an emf induced into the circuit by the change of flux linkages produced by a current change. When the emf is induced in the same circuit as … Read more
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Capacitors, Capacitance and Charge
Introduction to Capacitors A capacitor is an electrical device that is used to store electrical energy. A capacitor consists of two metal plates separated by an insulator called a dielectric. It stores electricity in the form of an excess … Read more
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Series and Parallel Circuits
Series Circuits The figure below shows three resistors R1, R2, and R3 connected end to end i.e. in series with a battery source of V volts. A series circuit Since the circuit is closed, a … Read more
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Root-mean-square (r.m.s.) value
We know that a current passing through a resistance has a heating effect, the magnitude of which we measure in watts, that is power is given by This shows that power (or heat) dissipated in a resistance is proportional to … Read more
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Resistance and Resistivity
The resistance of an electrical conductor depends on 4 factors, namely: The length of the conductor The cross-sectional area of the conductor The type of material The temperature of the material The resistance, R, is directly proportional to length L … Read more