Understand Electronics

Understand Electronics. Book • 2nd Edition • Authors: Owen Bishop. Browse book content. About the book. Search in this book. Understand Electronics.
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In this article we will try to learn regarding the basic circuit theory of electronics. We will try to understand the functioning of a few electronic components and also how they may be configured into small basic circuits. As shown in the picture a diode is a two terminal component and is recognized by a band or a ring at one of its ends.

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In the symbol the band is indicated by a straight line at the arrow point. The lead which is terminating from this side is the cathode and the other one is the anode. A diode will always allow a positive voltage to pass through its anode towards the cathode and block the other way round. Due to this particular characteristic, diodes are also used as rectifiers to convert AC into DC.

LEDs are quite similar to the normal diodes as explained above, but since LEDs are able to emit light in the process, are specifically used as indicators and in other forms of lighting purposes. LEDs are unable to tolerate high currents and therefore always incorporate a series resistor to dimension the required minimum current through them.

We all are quite familiar to this versatile member of the electronic family.

Schematic Diagrams

Transistors are basically used to amplify small electrical signals and also for switching purposes. Since most semiconductor devices are sensitive to high currents, resistors are employed to restrict a correct flow of current through them. The values of these resistors are dimensioned by calculating them using various formulas.

The following examples will clearly explain regarding how basic electronic circuits are designed:. As shown in the figure, the trigger voltage which is generally received from an IC output or some other similar source is applied to R1. The received current is correctly optimized through R1 and is used to bias the transistor T1 so that it may conduct and light up the LED connected to its collector arm. As explained above, resistor R2 has been incorporated to safeguard the LED from excessive currents.

The value of R2 is calculated using the following formula:. The value of R1 may be achieved using the following formula:. The LED in the circuit may be easily replaced by a relay, in case it becomes necessary to switch heavy loads at the output. The base resistor value then may also be calculated appropriately using the above formula. Sometimes we may find the source voltage to R1 too small and difficult for T1 to sense.

During such conditions an interesting modification can be introduced by conjugating another transistor with T1 as shown in the adjoining figure. As of [update] most electronic devices use semiconductor components to perform electron control.

Understanding Basic Electronics is Easy

The study of semiconductor devices and related technology is considered a branch of solid-state physics , whereas the design and construction of electronic circuits to solve practical problems come under electronics engineering. This article focuses on engineering aspects of electronics. An electronic component is any physical entity in an electronic system used to affect the electrons or their associated fields in a manner consistent with the intended function of the electronic system.

Components are generally intended to be connected together, usually by being soldered to a printed circuit board PCB , to create an electronic circuit with a particular function for example an amplifier , radio receiver , or oscillator. Components may be packaged singly, or in more complex groups as integrated circuits.

Some common electronic components are capacitors , inductors , resistors , diodes , transistors , etc. Components are often categorized as active e. Vacuum tubes Thermionic valves were among the earliest electronic components. They played a leading role in the field of microwave and high power transmission as well as television receivers until the middle of the s.

Vacuum tubes are still used in some specialist applications such as high power RF amplifiers , cathode ray tubes , specialist audio equipment, guitar amplifiers and some microwave devices.

I Can See Clearly Now

In April , the IBM was the first IBM product to use transistor circuits without any vacuum tubes and is believed to be the first all-transistorized calculator to be manufactured for the commercial market. From that time on transistors were almost exclusively used for computer logic and peripherals. Circuits and components can be divided into two groups: A particular device may consist of circuitry that has one or the other or a mix of the two types. Most analog electronic appliances, such as radio receivers, are constructed from combinations of a few types of basic circuits. Analog circuits use a continuous range of voltage or current as opposed to discrete levels as in digital circuits.

The number of different analog circuits so far devised is huge, especially because a 'circuit' can be defined as anything from a single component, to systems containing thousands of components. Analog circuits are sometimes called linear circuits although many non-linear effects are used in analog circuits such as mixers, modulators, etc. Good examples of analog circuits include vacuum tube and transistor amplifiers, operational amplifiers and oscillators.

Electronics

One rarely finds modern circuits that are entirely analog. These days analog circuitry may use digital or even microprocessor techniques to improve performance. This type of circuit is usually called "mixed signal" rather than analog or digital. Sometimes it may be difficult to differentiate between analog and digital circuits as they have elements of both linear and non-linear operation.

An example is the comparator which takes in a continuous range of voltage but only outputs one of two levels as in a digital circuit. Similarly, an overdriven transistor amplifier can take on the characteristics of a controlled switch having essentially two levels of output.

How to Understand Basic Circuit Theory? Designing Basic Electronic Circuits Made Easy

In fact, many digital circuits are actually implemented as variations of analog circuits similar to this example—after all, all aspects of the real physical world are essentially analog, so digital effects are only realized by constraining analog behavior. Digital circuits are electric circuits based on a number of discrete voltage levels.

Digital circuits are the most common physical representation of Boolean algebra , and are the basis of all digital computers. To most engineers, the terms "digital circuit", "digital system" and "logic" are interchangeable in the context of digital circuits. Most digital circuits use a binary system with two voltage levels labeled "0" and "1". Often logic "0" will be a lower voltage and referred to as "Low" while logic "1" is referred to as "High".


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However, some systems use the reverse definition "0" is "High" or are current based. Quite often the logic designer may reverse these definitions from one circuit to the next as he sees fit to facilitate his design. The definition of the levels as "0" or "1" is arbitrary.

Ternary with three states logic has been studied, and some prototype computers made. Computers , electronic clocks , and programmable logic controllers used to control industrial processes are constructed of digital circuits. Digital signal processors are another example. Heat generated by electronic circuitry must be dissipated to prevent immediate failure and improve long term reliability. Means to achieve greater dissipation include heat sinks and fans for air cooling, and other forms of computer cooling such as water cooling.

These techniques use convection , conduction , and radiation of heat energy. Electronic noise is defined [13] as unwanted disturbances superposed on a useful signal that tend to obscure its information content. Noise is not the same as signal distortion caused by a circuit. Noise is associated with all electronic circuits. Noise may be electromagnetically or thermally generated, which can be decreased by lowering the operating temperature of the circuit.

Other types of noise, such as shot noise cannot be removed as they are due to limitations in physical properties. Mathematical methods are integral to the study of electronics. To become proficient in electronics it is also necessary to become proficient in the mathematics of circuit analysis. Circuit analysis is the study of methods of solving generally linear systems for unknown variables such as the voltage at a certain node or the current through a certain branch of a network.

Also important to electronics is the study and understanding of electromagnetic field theory. Due to the complex nature of electronics theory, laboratory experimentation is an important part of the development of electronic devices.