Electronic circuits are an integral part of almost every technological advancement being made in our lives today. Television, radio, telephones and computers immediately come to mind.
But, electronics are also used in automobiles, kitchen appliances, medical equipment and industrial controls. At the heart of these devices are the active components. They are circuit components that electronically control the flow of electrons, like semiconductors.
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However, these devices could not function without the much simpler passive components that predated semiconductors by many decades. Unlike active components, passive components such as resistors, capacitors and inductors cannot control the flow of electrons with electronic signals.
As its name implies, a resistor is an electronic component that resists the flow of electric current in a circuit.
In metals like silver or copper, which have high electrical conductivity and therefore low resistivity, electrons can freely jump from one atom to the next with little resistance.
The electrical resistance of a circuit component is defined as the ratio of the applied voltage to the electrical current flowing through it. of it, according to HyperPhysics, a physics resource site hosted by the Department of Physics and Astronomy at Indiana State University. Georgia.
The standard unit of resistance is the ohm, named after the German physicist Georg Simon Ohm. Resistance can be calculated using Ohm's Law, which states that resistance equals voltage divided by current, or R = V / I, where R is resistance, V is voltage, and I is current.
Resistors are generally classified as either fixed or variable. Fixed value resistors are simple passive components that always have the same resistance within prescribed current and voltage limits.
Variable resistors are simple electromechanical devices, such as volume controls and dimmer switches, that change the effective length or effective temperature of a resistor when you turn a knob or move a control slider.
An inductor is an electronic component consisting of a coil of wire with an electric current flowing through it, creating a magnetic field. The unit of inductance is the Henry (H), named after Joseph Henry.
He was an American physicist who independently discovered inductance at the same time as English physicist Michael Faraday. A henry is the amount of inductance needed to induce 1 volt of electromotive force (the electrical pressure from a power source) when the current is changing at 1 ampere per second.
An important application of inductors in active circuits is that they tend to block high-frequency signals while letting low-frequency oscillations through. Note that this is the opposite function of capacitors. Combining the two components in a circuit can selectively filter or generate oscillations of almost any desired frequency.
With the advent of integrated circuits such as microchips, inductors are becoming less common, because three-dimensional coils are extremely difficult to manufacture in circuits 2D prints. For this reason, microcircuits are designed without inductors and use capacitors to achieve essentially the same results, according to Michael Dubson, professor of physics at the University of Colorado at Boulder.
Capacitance is the ability of a device to store electrical charge. The electronic component that stores electrical charge is called a capacitor.
The oldest example of a capacitor is the Leyden jar. This device was invented to store a static electrical charge on the conductive foil that coated the inside and outside of a glass jar.
The simplest capacitor consists of two flat conducting plates separated by a small gap. The potential difference, or voltage, between the plates is proportional to the difference in the amount of charge on the plates. This is expressed as Q = CV, where Q is charge, V is voltage, and C is capacitance.
The capacitance of a capacitor is the amount of charge it can store per unit voltage. The unit for measuring capacitance is the farad (F), named for Faraday, and is defined as the ability to store 1 coulomb of charge with an applied potential of 1 volt.
A coulomb (C) is the amount of charge transferred by a current of 1 ampere in 1 second.
To maximize efficiency, capacitor plates are stacked in layers or wound on coils with very little air space between them.
