Electronics — for Complete Beginners

Why is it called “electronics”?

It all begins at the atomic level, so we’ll have a look at atoms, how they vary from element to element, and how what we think of as “electric current” arises from that structure.

(Reminder: Please review each video lecture by downloading and reading the text version.)

Nope … it’s not about money, or the “Light Brigade”.

It’s about that little poke you sometimes get after shuffling across a carpet in your hard-soled shoes … or those dramatic shafts of white-hot energy that nature sometimes displays to thunderous applause.

We’ll see what causes it, and how we’ve learned to make it happen at will, and in controlled ways that help us get the day’s work done.

What’s magnetism got to do with electronics!?!

That’s a fair question, because electromagnetism is all over the place, working quietly for us in the background, and with little or no appreciation.

It’s safe to assume that if it’s “electronic”, it’s employing magnetism to some extent to enable it to do whatever it’s doing for us. So, as a budding electronics expert, magnetism is definitely a phenomenon that you’ll want to know something about.

Electronics is a branch of physics which, in turn, deals with the relationships between matter and energy mathematically.

So, yes. We’ll be “doing the math” now and then. But it won’t be anything more complicated than a 7th grader could probably handle.

This is a comprehensive introduction to what you can expect to encounter in this course.

We delve deeper into the nature of electric current, and the imbalance of charge that produces it.

What’s an “amp”; what’s a “volt”.

And we begin thinking about how and why materials differ in terms of their “conductivity” and “resistivity”.

(Don't forget ... please download and review the text version of each lecture before continuing to the next video.)

We think about the conversion of energy from one form to another, and the idea of power dissipation — what’s a “watt” and how it’s measured and calculated.

Greek prefixes are introduced, such as “mega-” and “milli-”, and what they mean.

The math concepts of “scientific notation” and “powers of ten” are also introduced and briefly discussed.

Why a special discussion of “heat”?

Because in electronics, heat is usually a bi-product of every useful operation, and must be adequately managed, else malfunctions and failures are bound to happen.

You will be encouraged to develop the attitude that — as an electronics technician, at least — heat is not your friend.

We’ll be thinking about resistance to current flow in much greater depth — what causes it, how it’s measured, and how it relates to voltage and amperage.

The most basic of electronic components is introduced; namely the “resistor”. The various kinds of resistors are introduced, along with a brief discussion of how they are made.

We learn about “Ohm’s Law”, and how to use it to calculate values of volts, amps, and resistance.

Resistors are the most common of all electronic components.

So let’s learn how to read color-codes, and find out what standard resistance values are commonly available.

Well, it’s time to roll up your selves and do some head-scratching over some simple circuit problems.

Then we’ll also talk briefly about variable resistors — “pots” and “trimmers” — and what they’re used for.

You can’t usually guess the function of electronic circuitry just by looking at its wiring or circuit board.

Certain diagrams and documents, created by designers and engineers during its development, become essential tools for the technician over the life of the equipment.

The lecture briefly introduces some of these resources, and some of the tools used to create them.

“Ground” and “Earth” … is there really any difference?

What’s all that “shorts” and “opens” stuff about anyway!?!

“Series” and “Shunt” are terms you’ll often encounter.

Maybe you already know what they mean. But we’ll go beyond that to see how those sorts of connections affect resistance values.

“Voltage drop” … well, probably not so much. But you’ll know about that too when you’re finished with this lecture.

Finally, what the heck are "Kirchhoff’s Laws", and why should we care about that!?!

Edison may have invented the electric light bulb, but if it hadn’t been for Tesla and Westinghouse, we might still be burning candles.

What’s up with alternating current anyway?

(Are you reviewing the text version of each lecture after watching each video?)

Alternating energy forms are very commonly encountered in electronics, quite beyond the AC which comes out of a wall receptacle, and certain kinds of electronic components respond much differently to alternating signals than they do to DC.

So, before having a look at those sorts of components, let’s find out about the nature of alternating energy by evaluating the characteristics of simple alternating current.

An “inductor” is the simplest of all electronic components, being nothing more than a coil of wire. But that doesn’t mean that it’s lacking in interesting and useful properties.

As you’ll soon find out, it is, among other things, the magical physical phenomenon that enables the electrification of your home and office.

The king of the inductive components is the transformer, and they come in all sorts of shapes and sizes. Here’s how they work, and what they’re typically used for.

Capacitors rival resistors for ubiquity in electronic circuitry. What’s capacitance? What are capacitors. How are they made … what do they do … why are they used?

We’ll talk about all that and more, and we’ll have a little fun creating a simple circuit that solves a real-world problem.

So many capacitor types to choose from … seventy-six pages of fine-print in the DigiKey catalog, a popular source of electronic components! What the heck is up with that!?!

Not to worry. We’ll boil it down to just a few choices which, for all practical purposes, will quite adequately cover whatever applications you happen to have … and which can be schematically represented by just three simple symbols.

Capacitors are never perfect, and their imperfections and failure modes are well worth knowing about. So, we’ll talk about that briefly also.

Remember “ELI” and “ICE”?

Unlike the simple resistor, coils and capacitors alternately store energy, and then release it back into the circuit. So how do we know what to expect from a circuit combining coils, capacitors, and resistors?

The answer is, trigonometric vector analysis … a simple tool that will help us figure that out the easy way.

In this part in our study of reactive circuits, we’ll learn how to evaluate circuits consisting of resistance and inductance ... whether connected in series, or in parallel.

Having gotten our feet wet in our study of RL reactive circuits, we move on now to the similar evaluation circuits consisting of resistance and capacitance … again, whether connected in series, or in parallel.

You guessed it was coming next, didn't you?

In this final part in our study of reactive circuits, we’ll have a look at networks that include resistance, inductance, and capacitance … again, whether connected in series, or in parallel.

Resonance (you’ll probably catch me sometimes saying “residence”) can mean many things. If you look it up in an online dictionary, you’ll be apt to find this: that condition of a circuit with respect to a given frequency or the like in which the net reactance is zero and the current flow a maximum.

After you’re through with this lecture, you’ll realize that is not actually accurate.

Resonance has some particularly useful applications in electronics, and you’re about to discover what they are.

An interesting thing happens when a variable-frequency signal is applied to coil and capacitor that are connected in series. There is, in fact, a frequency where that dictionary definition previously scoffed at is actually valid.

If you think about it hard enough, you should be able to figure out why that is true, before even viewing this part of the lecture.

But continue on anyway, and you’ll learn how to figure out what that special frequency is, how sharply tuned the circuit will be, and what resonance can be used for in electronics.

Resonance also occurs when a coil and capacitor are connected in parallel. The behavior of the network, sometimes called a “tank circuit” is essentially just the opposite that of the series resonant configuration.

Tank circuits also have their own unique applications which, you’ll discover, are essential to communications.

Back in the old days, the principle of the thermionic vacuum tube, at the most basic level, involved heating one element inside the tube to red-hot in order to generate free electrons, and applying a highly positive potential to a second element in order to attract those current carriers.

The operation of today's’ solid-state devices is, at the most basic level, a result of a natural phenomenon occurring when two slightly different types of semiconductor material are joined together, the interface being called a P-N Junction. We’ll see how that works in forming the simplest of all solid-state devices; the diode.

We’ll also briefly practice an exercise in perspective: conventional current vs. electron current.

PN Junctions become useful when exploited through the application of external potentials, called bias. We’ll see that that is, and how it affects the junction.

We’ll also learn about some very common diode types, and their applications.

We’ll briefly review the common Greek prefixes and suffixes, and how they relate to powers of 10.

Then we’ll go further, learning how to calculate using those exponential values, and seeing how that can greatly simplify the arithmetic.

From engineering genius to eugenics crackpot … the story, in brief, of the man credited with the invention of binary junction transistor and the birth of Silicon Valley.

We’ll briefly see how that story unfolded, and what happens when two PN junctions are fused together to form a single device called the “transistor”.

Discrete BJTs being used primarily for switching these days, we’ll focus on that, and the types of devices that commonly chosen for that application.

The development of a practical field-effect device originated through an effort to duplicate the functioning of a thermionic vacuum tube triode in solid-state form … that is, to control current flowing between two elements by means of a potential applied to a third. It took some twenty-years, but William Shockley finally figured out how to do that.

Here’s what he came up with, and how it works.

Delving into some of the finer points of circuit design with JFETs, we’ll touch on the concepts of conductance and transconductance, and have a look at some typical JFET characteristics.

Along the way, we’ll see how these devices are used in a couple of practical applications.

The Metal Oxide Semiconductor FET represents a departure from the PN junction paradigm, and has stolen the show from all other semiconductor types in switching applications.

Here’s why.

We’ll revisit our relay-driver circuit, to see how it’ll work with a MOSFET, instead of a BJT.

The CMOS scheme is introduced, and we’ll see how that lends itself ideally to both simple logic circuits, and “large-scale integration” applications, including random-access memory systems.

When “solid-state” is mentioned, one is apt to envision small, low-power devices, in applications like radio, TV, personal computers and cell phones.

In this section, we’ll be thinking about some solid-state devices that are designed especially for AC, and are commonly found in applications involving 120/240vac service power.

PN Junctions, and certain materials, are naturally light-sensitive. That attribute can be enhanced to produce devices capable of detecting the presence of light, and measuring its intensity.

We’ll have a look at how these devices, work, and some simple applications for the photoresistive and photoconductive devices.

More generally known simply as “photocells”, photovoltaic cells are very useful as a power source for portable equipment, They are also finding widespread use in practical electric power generation, as a so-called “renewable resource.

We’ll now have a look at how these devices work, and how they’re being adapted to those applications.

Piezoelectric materials have the ability to generate small electrical potentials in response to applied stress or, conversely, to change dimensionally in response to applied potentials.

This lecture very briefly describes how that works.

Piezoelectric effects are employed in a very wide variety of applications, including commonly used, everyday products.

We’ll see what some of those are, including even a do-it-yourself example.

The development of monolithic integrated circuitry engendered a dramatic paradigm shift in electronic technology. Over just the past sixty or seventy years, the products it has made possible have changed even the culture itself, and altered the path of human history.

It’s astonishing that much of this has resulted from the inventions and innovations of just a handful of very bright individuals … a few engineers and entrepreneurs, who have had far more influence on the development of life as we know it today, than all of their contemporaries in the realms of world leadership.

We’ll very briefly review how that happened.

As we approach the realm of monolithic integrated circuits, it needn’t be with foreboding over something that threatens to be formidably complex. Think of it as entering the midway of a carnival, with all sorts of colorful and fun rides and games to experience!

We’ll begin with the simplest of all such “chips” … those which just deal with zeros and ones … “on” and “off”, in other words, or “high” and “low” input and output states.

They’re called “logic” circuits, because they’re usually used to perform some simple decision-making task.

Flip-flop circuits are a workhorse of modern digital electronics. Primarily a logic element, they’re also found in all sorts of other applications. We’ll look at the basic flip-flop, and some more advanced versions designed to overcome some of its deficiencies.

Clocks, in the electronic sense, usually have nothing to do with telling time. We’ll also discover what that means.

Reminder: If the explanations of the digital circuits discussed in these videos seem difficult to follow, consider reviewing the lecture by downloading the PDF version, or reading the printed version.

Multivibrators are circuits that generate square or rectangular waveforms. This sort of circuit was invented way back in the early 20th Century, well before there was any practical use for it.   

A modern version of it is essential to the computer that you’re using right now. We’ll have a look at some modern versions, and will see what they’re used for.  

Before investigating the wonderful world of complex digital integrated circuits, it’ll be helpful to know something about the number systems such chips use.

It’s called the binary number system.

There are several special versions of the binary number system. The two most frequently encountered are called BCD, and Hexadecimal.

We’ll briefly investigate the nature of these two iterations, and find out what they’re used for.

Counting is frequently required in digital computers and other digital systems to record the number of events occurring in a specified interval of time.

There are several types of counters in common use, the binary ripple counter being the simplest.

More versatile than the simple ripple counter, the Binary/BCD, Up/Down counter is especially useful for event programming and alphanumeric display purposes.

The “4029” has been a very popular part for a long time. In this lecture, we’ll see how that works.

Operational Amplifiers have been mentioned a few times in the previous lectures, but without going into much detail about what they are, and the many ways that they can be used.

That’s the principal subject of this lecture. If you’ve been worrying about op amps being complex and difficult, you’re in for a nice surprise!

Op amps can do just about anything. Their original intended purpose was mostly to handle linear mathematical functions.

In this part of the lecture, we’ll see what some of the more commonly-used ones are.

One of the lessons that you should take home from any course in electronics fundamentals is that the performance of any sort of circuit will never be any better than its DC power supply.

Fortunately, with today’s monolithic DC voltage regulators, excellence in that area is very easy to achieve. This final part of the lecture will show you how.

Monolithic integrated circuits are not necessarily “either, or”. There is no reason why a single chip cannot include both analog and digital functions, and in fact many do.

One of the most unexpectedly successful is the simple “555” timer chip, which we’ll have a look at here.

In this lecture we’ll have a look at the ways that digital information can be interfaced with our analog world, and vice versa.

Time to say “Goodbye … and good luck!”