Crash Course Electronics and PCB Design

In this first lecture we take a look at the file resources, book for the course, parts list, and more.

General course overview discussing the depth and breadth of what we will cover over the lectures of the course and what to expect.

Introduction to electronics and electrical engineering with a brief run through of various electronic components to get your feet wet with concept, terms, and various units of measure.

Digital electronics is an abstraction of analog electronics, so we will start with digital systems, talk about ideas, concepts, units of measure, binary. And do a bit of hands on and look at various parts.

"Electronics" is the study of electrons and their behavior and use. In other words, what are the properties of the sub-atomic particles we call electrons? And how can we leverage these properties to perform work and build circuits? Therefore, we are going to start at the very beginning with our journey of electronics and understand the fundamental unit of charge -- the electron as well as what makes conductors conduct, insulators insulate, and what "semiconductors" are. This is one of the most interesting lectures, so take your time.

The action in every circuit element you can imagine can be described by two quantities -- Current and Voltage. Current is measured in Amps (A), while Voltage is measured in Volts (V). These every day quantities at first glance seem easy to understand, but they are anything, but easy to nail down. We are talking about moving charge around (electrons) under a potential field (voltage), so there are a lot of physics to understand what's REALLY going on -- And guess what, that's exactly what we are going to figure out!

This is Part II of our discussion about Current and Voltage. We will focus more on how to generate currents and voltages, batteries, as well as do a good amount of bench work.

Batteries in general are chemical devices that can generate a voltage, store charge, and perform electrical work for us. However, working with batteries, connecting them in series and parallel and understanding the physics and behaviors of batteries in these configurations can be tricky. In this lecture we dive into this subject as well as start building some primitive "circuit analysis" tools.

This lecture introduces you to the concept of DC (Direct Current) vs AC (Alternating Current). DC circuits in general have a fixed ground at 0 volts, and the signals may all be positive, but not necessarily. For example, a DC circuit might have a 5V supply, with an amplifier that amplifies a small signal from a microphone, this signal could potentially go below ground! So, is this a DC or AC circuit? It's both! On the other hand, when you plug a light into a wall socket, the current coming out is clearly AC, its direction alternates 50/60 times a second, but parts of the circuit inside the light fixture/PCB might be DC. 

Thus, the term AC/DC circuits is a bit of a misnomer, and its better to think of all circuits as have both positive signals and negative signals potentially. However, if signals are changing as a function of time, they must be analyzed with "AC" techniques and Ohm's Law must be adjusted to account for "reactive" elements and the idea of "impedance" (which we will get to later), but strictly speaking even though we need AC techniques to analyze some signals/circuits, said signals might not be AC signals unless the current alternates in direction under the definition. So, like many things, the idea of AC and DC circuits has a lot of shades of gray. We will try and clear all this up in this introduction lecture.

Circuit analysis is a mathematical process or determining the voltages, currents, and general behavior of an electrical circuit. There are many tools to do this, but one of the most important is Ohm's Law which relates voltage to current and resistance in a form like V=I*R (which we will cover in this lecture). Of course, Ohm's Law is a model, an approximation and works under conditions met by our types of circuits. Also, once we have a handle on Ohm's Law we can use it to compute "power" which is an abstract concept and misunderstood many times, so we will take this lecture slow.

Now, that you're warmed up with Ohm's Law in the previous lecture's introduction. Now, we are going to really dig deep into the use of the law to analyze many real circuits. As well as jump on the bench and work some circuits there.

Continuing with our deep dive of Ohm's Law and beginning circuit analysis, we are going to add new components such as LEDs to the mix, buttons, and other interesting electronic devices and build up more complex circuits. We will analyze these circuits on the black board and then build them on the bench and compare our mathematical analysis to what we see on the bench in the real world.

The resistor is something you will use a lot of in your electrical designs, unfortunately the values of resistors aren't written on the devices (due to their small size) in plain English. The values are encoded typically in a color code. This type of coding is actually used for other devices such as "inductors" which we will discuss later. But, there are exceptions of course, there are some resistors which DO have their values written on them! But, we all need to know resistor color code, so we are going to learn it here. Also, we will add another component to our design repertoire -- the Capacitor, just an introduction, but enough information, so we can have some fun!

If you are new to electronics as a hobbyist then you are comfortable with resistors, don't mind capacitors, but the utterance of the word "inductor" sends chills down your spine :) If this is true, then you are in the right lecture -- we are going to break down inductors from every angle, and when we are done, they will have nightmares about you!

Inductors are the basis of more complex electrical devices. One such device is the "Transformer". Transformers rely on the generated magnetic field created in inductors and the magnetic flux impinging on other nearby inductors which in-turn generates a current in the other inductor. This property can be leverage for voltage and current amplification as well as many other useful task. In this lecture, we are going to learn about the operation, construction, and mathematical modeling of transformers as well as see them in action on the bench.

Diodes are arguably the simplest of the "semiconductor" devices and have many uses in filtering, rectification, current steering, clamping, and more. In general, diodes only allow current to flow in one direction (although depending on the diode type this isn't always true). There are many kinds of diodes and in this 3 part lecture we will learn about silicon diodes, schottky diodes, zener diodes, and more. And of course, get on the bench and work with them in a number of hands on experiments. In this first part of the series, we will get to know the physics of diodes, some terminology, what they look like, and some basic uses. Then in the remaining lectures we will learn more and more advanced uses and circuits.

In Part II of our diode discussion, we talk more about silicon diodes, zener diodes, and schottky diodes. We learn about rectification circuits, power supply design, as well as some practical experience looking the parts up online.

In this final diode lecture of our 3 part series we experiment more with silicon diodes, LEDs, as well as design a "Zener Voltage Regulator" on the bench.

Transistors are one of the most powerful electronic devices in-as-much as they enabled most everything you think of as "modern electronics" such as amplifiers, filters, electronic switches, and the digital revolution. Before transistors many of these functions were performed with vacuum tubes are many orders of magnitude the power, slower, and size of transistors. In this 3 part lecture series, we will review the physics and models for the BJT (Bipolar Junction Transistor) which is a 3 layer device and the most basic form of a "transistor".

In Part II of our Transistor lecture series, we will wrap up the theory for a moment, and jump onto the bench and build some circuits, analyze and measure what's going on with them, and see if they match what we believe their theoretical behavior should me.

In this final lecture of our 3 part Transistor series, we cover more theory as well as put it to use with controlling very large loads with transistors, i.e. motors. One of the most common things engineers want to do with transistors (or FETs which we will learn about) is use a small current/voltage to control a much larger current/voltage. Transistors are very good at this and this construct can be used to drive heavy loads such as motors, lighting, etc. In this lecture, we are going to get on the bench and build some cool motor drivers and check out some very expensive micro pumps while, we are at it! 

This is part 1 or a 2 part lecture on MOSFETs (Metal Oxide Semiconductor Field Effect Transistor). Unlike, BJTs (Bipolar Junction Transistors), MOSFETs or simply FETs are not Current controlled switches, but Voltage controlled switches. FETs are used to construct just about all our digital technology, have incredible switching speeds, ridiculously low current and power requirements, and can be very small on the order of a few layers of atoms! In this lecture, we are going to learn about basic FET construction, how they work, and some simple mathematical models of their operation. 

In Part II of the MOSFET lectures we learn about designing with FETs, how to model them in circuits, analyze them along with other passive components and use them as "switches". Then we jump on the bench and build more circuits with them, this time we don't play around with a little motor, but a very high current heating element and build a remote controlled (via switch) heater!

Now that you have some basic electronics knowledge under your belt, it's time to slow things down and take a look at the tools, instruments, and methods use to actually build and analyze real circuits. This 3 part lecture series is probably one of the most glossed over information in most Electrical and Electronic degree programs. You learn everything about circuit analysis, how to design circuits on paper, simulate them, but you don't learn how to "build" actual circuits in the real-world, use test equipment and the myriad of options available. This information is usually learned over years of experimenting or working as a tech under someone, etc. In this lecture series you're going to see how to build circuits on solderless breadboard, solder, wire wrap, use oscilloscopes, meters, power supplies and much, much, more...In any event, we are going to hit it head on, so kick back your feet, this will be a lot of fun!

In this part of the Fabrication and Tools lecture series, we are going to cover wire wrapping, soldering, solderless breadboards, power supplies, reflow oven and more

In this final lecture in our 3 part Fabrication and Tools series, we are going to build a small "LED Flashlight" project end to end. We are going to make decisions on fabrication techniques (should we solder, wire wrap, build a PCB?) We will build the circuit by hand piece by piece, testing along the way, and when complete, we will have a finished LED Flashlight!

In this lecture, we continue building our tool chest for analyzing circuits, do some review using Ohm's Law, and then work on the bench with a couple fun experiments showing how size and shape relates to resistive elements in a circuit.

Ohm's Law helps us compute the current and voltage in a circuit element, but we need more complex techniques to compute the currents and voltages in networks of components connected in various ways. This is where "Kirchhoff's Laws" come into play. These laws give us tools to mathematical compute voltages and currents in circuit nodes, and loops. You will learn that very simple equations can be formed that model a circuit, and then these equations can be solved using high school math techniques or more advanced matrix operations. Don't worry if you never learned how to solve systems of equations, like all the math in this course, I will take it slow. Even those of us with math degrees, get a little rusty over the years!

In this lecture, we put our circuit analysis skills to the test and take a fairly complex DC circuit with multiple sources, branches, voltage divider, and bring it to its knees and figure out every single voltage, and current in the circuit. This lecture is a lot of fun -- it's like watching a murder mystery unfold in front of your eyes. I will do all the work though, so you can take your time and follow along!

Although we have seen voltage dividers and worked through them before, we are going to dig deeper, slow down to really appreciate voltage dividers and really understand not only their "action", but to understand concepts like "stiffness", changing impedance with them from source to load and how to scale AC signals with them as well. Get ready for some theory, bench work and experimentation and some fun with the oscilloscope.

We take a break from circuits in the real-world for a bit in this lecture and explore "Circuit Simulators". One of the earliest and still most popular simulation engines is called SPICE which stands for "Simulation Program with Integrated Circuit Emphasis". Honestly, sounds like they reversed engineering the meaning AFTER they came up with the name! In any event, SPICE is a technology that allows you to model electrical circuits in the computer and then run a simulation to see what the circuit will do. 

Although, SPICE can rarely run large circuits in real-time (without a quantum computer), it does run fast enough to solve for circuit analysis problems and even AC and signal processing, digital circuits, near real-time as long as the circuits aren't too complex. With VERY powerful desktop and workstation class computers you can simulate entire microprocessors, and reasonably complex analog circuits. We are going to learn about the SPICE language as well as tools that use SPICE type engines under more graphical, user friendly GUIs.  

Section 4 of this course is massive with emphasis on MASSIVE. So, this lecture is a short video road map to everything we are going to cover to set the expectations of the section. Honestly, this is one of my favorite sections of the course since you will leave knowing so much more than you entered with. And you will know what you don't know which is very important in Electrical and Embedded Engineering. The more you learn about what you don't know, helps you STOP doing things the wrong way and go research how to do them the correct way. 

Electronics design is full of interesting components such as resistors, inductors, capacitors, transistors, diodes, and more. However, every circuit needs an ON/OFF switch, so we are going to start with looking at some "mechanical" components, or otherwise referred to as "mechanicals" which means parts that don't have electrical functions like inductance, capacitance, amplification, etc. they are just made of metal, plastic, paper, and so forth and are used to connect things, interface things, and for user interaction. The first type of mechanical we will discuss is the simple "switch" which isn't as simple as you might think!

This lecture covers one of the most useful electronic devices; the "Potentiometer" or otherwise known as the "POT". POTs are variable resistors that can be adjusted from 0 ohm to some value, 1K, 10K, 1M ohm, etc. Very useful in circuits where you want to adjust a voltage, volume, amplification factor, cut off frequency, or some other analog value.

Capacitors are very complex devices (like inductors), their action is based on the accumulation of charge (electrons and holes) on two metal plates separated by space. This creates an electric field and all kinds of interesting properties come into existence. But, sometimes its better to just use an electronic component in some context to see what it does, before we understand how it does it. For example, everyone knows what an LED is these days, but LEDs are quantum mechanical devices and very complex if you really want to understand them. But, anyone can hook a 9V battery up to some LEDs and they will turn on, regardless if you understand WHY they turn on. Alas, we are going to put the capacitor to work to "couple" AC circuits, and show one of its uses is to filter DC signals and pass AC signals -- along with bench demos and experiments of course!

Here we get into the physics of capacitors and the C=Q/V model where C is capacitance in Farads, Q is charge in Coulombs, and V is Volts. We will learn how capacitors are made, how they work, and how they network together. For example, when you put two resistors in series, the resulting resistor is simply the sum of the two resistors, but how does this work with capacitors for series and parallel combinations? We will derive it all on the blackboard, so you see the math once in your life, and then you can tuck the analysis away, and simply use the formulas.

If you're an electronics hacker, you probably play mostly with digital circuits, Arduinos', Raspberry Pi's, and so forth. But, at some point, you might have heard about "RC Circuits" or "RC Time Constant" and wonder what that's all about? Well, your wondering stops here! We are going to learn about RC circuits, that is, circuits with a Resistor and Capacitor (usually in series), and what happens when you apply a voltage to this simple network? How does the capacitor charge? Then how does it discharge when you remove the voltage? And what's the math that models all this? 

This subject is fairly advanced EE concept and we will take our time, but rest assured, I will make this fun, and with bench work, demos, and signal analysis on the Oscope you hopefully will finally understand RC Circuits if you have had trouble with them in the past.

Inductors constantly get a bad rep. I think the reason why is they really are only useful at very high frequencies, unless you have REALLY large inductors. So, most electrical/embedded engineers can literally get through and entire career and never use an inductor in a design! Therefore, its one of those things, that people learn in school then forget about. But, I want you to LOVE inductors, I mean, you run a current through them, they generate a magnetic field that stores energy (what!) and then they can be used in filters, oscillators, transformers, and motors. 

Inductors are the basis of so many of our machines and high power circuits, how can you not love them! However, before we start this relationship, we need to crack them open, look inside, talk about flux, current, fields, the right hand rule, induction, and a lot more. But, I promise when you finish this lecture (which you may have to watch a couple times), you will not be afraid of these little guys anymore!

After a quick review of RC circuits, so you can keep them straight from RL circuits, we will play with one of the most advanced tools on the planet -- MATLAB (Matrix Laboratory) - which if you have never heard of it is a tool that you can use to model just about anything with a C-like language and support for very high level mathematics. That's where the term "Matrix Laboratory" came from, but that term hardly does this tool justice. Scientists literally use this tool to figure out the secrets of the universe, so it will do nicely as a modeler for RC and RL circuits. Finally, the lecture will finish off with more RL circuit analysis and derivations.

We have learned about RC and RL circuits and seen one way to understand their charging and discharging or more accurately energizing and de-energizing when referring to inductors. But, as we move into steady state AC circuits and we are interested in understand not what happens the moment a current flows in an RCL circuit, but what happens when an AC signal is continuously applied? This is the starting point for understanding complex impedance, phasors, and more advanced AC analysis. But, first we are going to simply start with understanding the relationship between current and voltage in both the capacitor and inductor along with some tricks to remember the differences between each since they are analogs of each other.

If you are following along the lectures, you probably realize we need to take the math up a notch to deal with unfortunate fact that current and voltage are out of phase in capacitors and inductors due to their "reactance". To deal with this property in a consistent mathematical way, we are going to introduce the concept of "phasors" and I don't mean something from Star Trek :) But, rather -- a mathematical tool based on imaginary numbers that helps us tracks the voltage and current as a polar value rather than a fixed magnitude -- I know, sounds a bit crazy, but it will make more sense after you view this lecture - And yes, I had to throw a Star Trek reference in there!

Now that you have a handle on phasors, we will use them to analyze circuits in a more compact form and write currents and voltages in the circuits as phasors. This process will help make clear the concept of "Complex Impedance" which is a method of taking both the real resistance a circuit element has along with the reactance it has and using imaginary numbers (or phasors) to try and represent these values. As you will see down the line in later lectures, sometimes we want to use simple reactance to analyze a circuit, other times phasors, but when you need to bring out the big guns, "complex impedance" and using imaginary numbers always works, is clean, and very consistent. The following lectures will touch on all of these subjects.

We have been using phasors as mathematical objects without worrying too much about what they are really representing in our circuits. In this lecture, we are going to clear that up, and bring "Imaginary Numbers" into the mix, and connect the dots. If you recall from high school, imaginary numbers have a real part, and an imaginary part. The imaginary part isn't imaginary at all, its based on the concept of the sqrt(-1) which is called i, or j for electrical engineers. When you add a real number and imaginary number, you can do so abstractly by thinking of a 2D plane. One axis is the real part, the other the imaginary part, so you can use the real part to hold one piece of information and the imaginary part to hold another, and never will they mix. 

This is a very useful property is mathematics, signal processing, radio, lots of things. And this real/imaginary combination is called a "Complex Number". We will use this math to represent phasors and complex impedance, but we need the math, so let's get to it.

Here we use our new knowledge of complex phasors to completely analyze an AC circuit, then we will simulate it, and finally build it to see if everything matches our calculations.

We circle back to voltage dividers, but instead of a simple DC circuit with resistors, we perform an AC analysis of an R/L voltage divider, and completely compute everything going on in the circuit. 

In this lecture we ease into the concepts of low pass and high pass filters, but rather that design a filter, we simply look at the same kind of RC and RL circuits we have been analyzing, but pay close attention to how things change as a function of frequency. I recommend watching a couple times if you need to, there's a lot here -- we do blackboard and theory, build simulations with Proteus, and then go to the bench and build the circuits and make real-time measurements with the Oscope and more. This is one of my favorite lectures, definitely in my top 10! 

In this BONUS lecture, we turn the danger level up to high and build and analyze a real line AC circuit. We are going to take our little RC circuit, build a model of it, excite it with low voltage, then take it to the bench and using "Power Electronics" test equipment power the circuit up and make measurements. Although, I like to joke around, this is a great lecture to learn safety measures when experimenting with AC line voltage. The truth is it can be very dangerous, so please pay attention to the safety measures outlined here if you want to experiment with power electronics yourself -- that's said, let's go blow some stuff up!

Using complex impedance analysis, we extract out the frequency dependent terms in a low pass filter and learn about "Transfer Functions" and how the filter's response changes as a function of frequency f.

When observing the natural world, many physical properties of matter, or energy, etc. many times its better to use a logarithmic scale rather than a linear scale. For example, when talking about amplification, we might start with a signal in the nano-volt range and have to amplify it into the volt-range. Therefore, we aren't talking about factors of 1.4. 2.0, 3.0, etc. we are talking about powers of 10, i.e. 10, 100, 1000, 10000, etc. Thus, in electronics as in many other fields the idea of being able to talk about logarithmic scale behavior or powers on n behavior leads us to the "decibel". 

This term, and concepts thereof, are misunderstood by many. After this lecture, go find an EE with a BS/MS degree and give him/her some simple problems / questions relating to dB scale problems, I bet they can't answer! This stuff isn't hard by any means, but its not intuitive and unless you work in certain fields of electronics, you simply don't work in dB scales all day and get rusty! So, this is a great lecture, a nice break from the hard core stuff we have been doing.

We revisit our favorite circuit, the RC circuit and use it as another example to investigate real-time frequency response and "see" its low pass behavior. We start with theory and then jump to the bench, and play with the circuit to see its practical use and -- limitations. You don't get anything for free in electronics!

The twin lecture of the previous low pass filter coverage, here we do the same thing, but with the high pass filter configuration by simply swapping the position of the R and C in the circuit -- yes, it's that easy! Again, theory and bench work, don't miss this one!

The poor inductor just gets no respect! Well, in this 3 part lecture series, we will show why it deserves respect and so much more, but also why the inductor is more or a very high frequency device and thus why it's not so popular with digital designers and hobbyists. In this lecture, we will work with the inductor to make a low pass filter.

In the previous lecture, we analyzed the low pass filter configuration of the inductor, now we turn the tables and swap the parts which results in -- you guessed it, a high pass filter.

In the final lecture of this 3 part series, we take our knowledge and theory about inductor based low/high pass filters, and use it to construct some circuits on the bench and see how they respond in the real world. What's interesting about this lecture is if you compare it against our capacitor based filter lectures, you will see some marked differences in the accuracy of the filters due to the tolerance of the parts, and Q or "quality" of the parts. Very important material, take your time and have fun!

Now that we understand AC analysis, we are going to circle back to diodes and experiment with them with AC signals and see how diodes can be used in this context. Some of the topics we will discuss are half wave and full wave rectification, using diodes as voltage regulators and more.

Moving on from silicon diodes in the previous lecture, we kick it up a notch with Schottky and Zener diodes. Here we explore more advanced applications such as power supply design, protection diodes, voltage clamping, and finish up with implementing digital logic functions with only diodes!

In this 2 part series we're going to take the previous diode theory and lectures from the blackboard to the bench and build many of the circuits we explored. In part 1, we will tackle half wave and full wave rectifiers and power supply front ends. Then in part 2, we will finish up with building and testing a zener voltage regulator.

In part 2 of the diode bench work series, we build a complete zener voltage regulator circuit and exercise it with various loads. Not only will you learn about zener regulation, but additionally terminology and concepts like "line regulation" and "load regulation" will be reviewed to help you when designing power supplies or using one off the shelf. 

Taking advantage of the very small forward voltage drop of Schottky diodes (250-350mV roughly), we leverage this feature to develop more logic gates and explore the limitation of diode-resistor logic. Of course, you would never use discrete diodes to implement logic gates; however, once in a while you want to sum a couple analog or digital signals, OR, or AND then, etc. and a couple 1 cent diodes might do exactly what you need without resorting to a full on gate IC. Moreover, Schottky diodes are used all the time in power supplies as "Power ORs", that is to "OR" currents, and steer currents in one direction, but without the penalty of the 0.6-0.8V forward drop of Silicon diodes.

This lecture is the first in a series of "Power Supply" lectures focusing on using off the shelf voltage regulators (linear and LDOs) as the base part to develop each power supply. A lot of practical knowledge as well as bench experiments and builds. 

In this lecture, we dig deeper into power supply design. We learn about IC selection, types of power supplies, more on filtering, heat management and fabrication of very small power supplies based on SMD (surface mount device) components.

You can't talk about power supplies without talking about the famous 7805 5V voltage regulator. Even though, these days you would rarely use an old school 7805 (there are modern replacements that are much better). The 7805 is still a good design example, and something you will find in a lot of hobbyist based designs to this day, so we are going to cover it for posterity since it's the "Hello World" of power supplies!

We continue to develop our general digital power supply by adding support for 3.3V to the outputs. Also, theory and practical considerations for the topology of the power supply are discussed, and pro's and con's of various approaches. Finally, we build the new 3.3V on the bench and test it out!

In this lecture, we take our 5/3.3V power supply design and learn how to power it directly from an AC line source or "offline" in other words. Thus, we will talk about practical transformers, transformer selection, connecting to AC lines, safety measures and much more. 

In the previous lecture, we discussed much of the theory, plans, and details to select, and connect our power supply front end directly to AC lines with a step-down transformer. In this follow up, lecture we get on the bench and work with the line AC power and make the connections, make measurements and exercise many safety precautions. I like to play around and joke, but AC is deadly serious, so please follow my safety precautions if you want to try this experiment for yourself. That said, let's go blow stuff up!

This lecture is worth its weight in gold -- It really is. As a professional embedded engineer, I can't tell you how many times, I have been handed a PCB designed by someone else, including a power supply, that doesn't work, or works part of the time with random failures that make no sense. 9 time out of 10, it's not the digital design, but the POWER SUPPLY DESIGN. Moreover, the power supply design is "ok" in many cases, usually a reference design from the manufacturer of the regulator IC, but the power supply is "noisy". And this creates problems with all kinds of electronics; digital and analog. Therefore, in this lecture, we are going to explore one of my favorite subjects -- Noise identification and reduction in power supplies. 

Amazingly, with just some rudimentary techniques, you can completely clean up noise in power supplies and better yet, I will show you how to "see" the noise, which will be shocking to most since its just horrible to allow such unclean power into your nice electronics. So, buckle in and let's kick this lecture into gear!

Although we have covered transistors before, in the next series of lectures we are going to explore much more complex features and uses of BJT transistors such as switching and amplification. This lecture serves as a quick refresher on the subject and brings in a few new ideas briefly.

In this lecture, we are going to break down a single BJT transistor and learn about how to "model" a transistor with a basic, but yet very useful model. You will learn about base, collector, and emitter currents, gain, biasing, and much more. This lecture will be our first in a series breaking down how to design and analyze transistor amplifiers and other interesting circuits that can be created with transistors. That said, this lecture is very important, since it's a foundation, so go slow, rewind if needed, and try to follow along with the simulations after you watch the lecture.

This is another one of my favorite lectures! In this lecture, we are going to use the information learned in the previous lecture about the transistor action and model for it, and leverage it to build some very useful circuits such as voltage regulators and constant current sources. Along the way, you will see more on "biasing" such as voltage divider and zener biasing, as well as some tricks such as taking advantage of the base-emitter junction forward voltage drop. I think I even throw in some "impedance reflection" -- the method of using the transistor itself to make a load or source look larger or smaller than it really is! Anyway, lots of cool stuff!

This lecture illustrates one of the primary uses of the transistor and that is for amplification. In this case, "small signal" amplification. In other words, how do we build a transistor circuit, so that we can insert a small signal (maybe uV to mV) and get out an amplified signals (10-100x), but without distortion? This is where many of the technologies we have learned will all come into play; transistor models, biasing, filters, etc. we will put them all together and build an amplifier.

Down the rabbit hole we go... Of course, we are just getting started with transistor amplifiers, there are 1000+ page books written (100's of them) just on transistor amplifiers! Therefore, this is a BIG subject, so the next topic we are going to cover is common emitter transistor amplifiers. In fact, you can have common emitter, common collector, and even common base (not very useful). However, common emitter amplifiers are VERY useful, since we can get voltage gain out of them which is of course a good thing! This is a big topic, so we will have a couple lectures on this subject matter to completely cover it and build enough on the bench to feel comfortable with common emitter amplifiers.

We wrap up our common emitter amplifier lectures with a detailed and brutal analysis of what's going on. This lecture is like watching a detective novel unfold before your eyes. It's a long video, and it's a lot of math, but I promise I make it as "fun" as it can possibly be. Moreover, the method of analysis performed here in this example to derive the gain of the circuit is a very common approach, so even if you're math skills are not Jedi level yet, just follow along with me and watch, so you see this at least once. 

THIS lecture is VERY important, so take your time, take breaks if needed, but get through it -- it's worth the payoff.

In this lecture, we take our transistor amplification and driver knowledge to the bench and build a circuit to drive a very big load -- a motor! Of course, we don't stop there -- being the analog experts we are at this point, I want to show you a "noise analysis" of the circuit and what powering motors from your power supplies do to the power rails -- motors are VERY noisy. 

Then we will work to reduce the noise in the motor, and induced noise elsewhere. This is a very important lecture if you plan on doing anything with power electronics and want to have any chance that your electronics will work properly. Don't miss this one!

In this lecture, once again we take our theory and math and put it to the test with a number of voltage regulation circuits we will build on the bench and analyze in real-time. These circuits are little gems and show you that you don't need a big IC to perform regulation, you can do it yourself in a pinch with a transistor, diode, couple of resistors and caps.

This is another don't miss lecture! Here we design and build an audio amplifier and even learn about microphones! This is one of the best bench experiment videos in the course. Starting with nothing, we are going to take a single transistor, build an amplifier, bias it, set the gain, connect a speaker and microphone (learn how electret mics work) and end up with a complete single stage audio amplifier. And of course, unlike just copying the circuit from internet, you will understand every single nanometer of it! And with that knowledge build better amplifiers!

In this lecture, we bid farewell (for now) to analog electronics and start our journey into Digital Electronics. But, like everything we do, we aren't going to rush, rather we are going to take a look at how digital logic gates are constructed using TTL (Transistor Transistor Logic) and run through how to design gates at the transistor level (albeit simplified version) to get a feel for what's going on "inside" digital ICs. Additionally, we will cover a great deal of new concepts, terms, learn about logic levels and different "families" of digital gates. A lot to do, let's get started!

Based on our work in the previous lecture about digital logic and using transistors to implement logic functions, we take that knowledge to the bench and build a series of working logic gates; including NOT, AND, NAND, OR, and NOR. With these simple constructions, just about anything can be built. If you so desired you "could" build an entire computer with discrete transistors! Of course, you would never want to, but back in the 1950's and 1960's that exactly what they did -- can you imagine that? Now, a single modern CPU/GPU has billions and billions of transistors (around 20-25 billion transistors is the record these days). 

Once we climb up the food chain a little bit from simple "combinatorial" logic circuits, and we want to build systems that have state, count, and run at a specified time interval, then we have to talk about "clocking", "oscillators" and related subjects. In other words, to build digital logic that is "clocked" by a single time reference, first, we need to be able to generate said time reference or "clock". This is what this lecture and the next is all about. We are going to learn about XTALs and their use as timing references and how that works. How oscillators work. And finally, we will take all our new knowledge and bring it to the bench and build a number of clock circuits, analyze them, see how MHzs' oscillators or XTAL based clocks perform. And ruminate about all our findings. There's a lot of practical information here, so another "don't miss" lecture.

In part 2 of the clock series, we look into more theory about oscillation criteria, dig into more detail, and continue working on our bench clock circuits and further analyze with the oscilloscope.

The 555 timer IC is one of the most famous (and useful) ICs' ever created. It's right up there with the 6502 microprocessor. Amazingly, the 555 is a very old IC, it's from the 1970's if you can believe that, and still used today in countless timing circuits. Now, don't get me wrong, you're not going to clock your 5GHz next gen processor with a 555, but you can build many useful timing based circuits with the 555 timer. That said, we are going to take a look at its data sheet, look at some of the basic configurations that the 555 can be used to build, and then of course get on the bench and build a working circuit with it. So, plug in and let's go!

This first lecture of this new section is 100% digital! You have graduated from analog electronics to digital design now, so pat yourself on the back. Of course, we are far from done with using analog electronics and there's more to learn, but from here on out we will mostly be discussing and learning about digital electronics and thinking of analog electronics as "support hardware" in our digital designs as we power them, interface them to the real world and whenever we need to deal with analog signals. That said, this "kick off" lecture focuses on learning the language of digital systems; binary, hex, Boolean algebra, and thinking in 1's and 0's for a change. 

This lecture requires a shift in thought process, so don't worry if it seems overwhelming initially. As usual, I like to introduce a subject many times in many ways, so anything here that you deem hard to understand, rest assured you will see it many more times and in different contexts to make it easier to grasp. Thus, without further ado, let's take the red pill and see how far this rabbit hole goes...

If you're not a software engineer/programmer or electrical engineer, then your whole life you have probably only worked with base 10 mathematics i.e. the decimal system. This is the number system we use every day, e.g. a number such as 159 really means 1*100 + 5*10 + 9*1. In other words, each place from right to left is a base 10 multiplier 1, 10, 100, 1000, etc. You can add, subtract, multiple and divide these numbers and have been trained to do so your entire life. But, there are countless other number systems based on "base n" mathematics where n can be anything. For example, binary is base 2 math, hexadecimal is base 16 mathematics and so forth. That said, in each number system we can perform similar operations to addition, subtraction, multiplication, and division. The question is "how do these operations work in each of the base n number systems?". This is the main topic of this lecture. We will be focusing on binary (base 2), and hexadecimal (base 16) and comparing it to decimal (base 10) as our anchor. 

We are going to learn in detail some of the laws of algebra as they pertain specifically to base 2. These laws are commonly known as Boolean algebra, and due to the nature of binary systems there are some very interesting shortcuts which are encompassed by what's knows as DeMorgan's Laws or theorem. This material is a lot of fun, and if you're a mathematics major or it's an interest of yours, you will really find this interesting. Regardless, it's absolutely necessary for our understanding of digital logic design and optimization.

In this lecture we are going to open up a single digital gate and really analyze what's going on from an input/output perspective at the analog level. This will be done in the context of learning a collection of new terms that will help us describe the properties, behaviors, and operation of any kind of digital gate or IC. This whole subject will be facilitated by looking at "data sheets". We have seen data sheets before in passing, but never really dug into them before. Now, that changes, we are going to look at data sheets in detail here, how to read them, use them, and how to NOT take every thing written in them as law, since they are written by humans, and tend to be flawed with errors, typos, etc. So, take everything with a grain of salt. 

Anyway, this is one of the most useful lectures as it covers a subject that is rarely covered in an EE degree -- and that's parts selection and optimization via data sheet review. Let's begin and see what we find.

When I did my EE degree, I had already been playing with electronics for almost 15 years (since I was a small child), so I had a huge advantage over the other students. Therefore, I could focus on the hard stuff like timing diagrams since I knew a lot of the basics already. Timing diagrams are one of those things though, that if you don't learn them early, and feel comfortable with them, they will haunt you, your entire career. Timing diagrams are basically abridged graphical annotations of how an IC works from a timing and signaling perspective. The problem is, there is no consistent way to draw them. Each engineer, company, etc. tends to do them their own way, sure there are similarities, but each data sheet, from each company, from each engineer, always takes a little work to "decode". 

Alas, we are literally and figuratively going to slay this dragon together, and take a look at how to read and understand data sheets, mostly digital information, but still in general, you will know how to navigate a data sheet and timing diagrams and not be scared silly when you see a crazy timing diagram like from a DRAM!

In this lecture we take a ride on the mechanical side of things and look at various IC "packaging". In other words, ICs can come in many shapes and sizes. And over the years, these have become smaller and smaller as a trend of course, but you can still buy old school "through hole" ICs and parts. We will take a look at ICs from the 1970's to the current state of the art, their pro's and con's as far as PCB design, fabrication, and how to work with them including mounting techniques as well as discussions about heat management.

Once again we will do battle with binary mathematics, but this time instead of thinking of binary numbers as signals in gates, we are going to abstract them a little to a higher level, and this will be more a practical "Computer Science" lecture on the material leading up to how to use what we know to build digital adders.

In this lecture we discuss the difference between TTL and CMOS based logic families with respect to interfacing them together. For example, how do you interface TTL 5V to CMOS 5V? What about LVC 3.3V to TTL 5V? And so on. Countless possibilities, but all are governed by analog concepts, so we will be able to crush it here and bring some of our analog knowledge to the table again to help untangle this mess.

In this unique lecture, we will review and explore more about actual circuit fabrication techniques. At this point, we have a lot of tools in our analog arsenal and we are getting a respectable stockpile in our digital war machine, but if we can't BUILD circuits then it's all for nothing! Therefore, once again, we take a detour and talk about all things mechanical and how to build circuits -- techniques like solderless bread boarding, wire wrapping, PCB design, and more will be discussed.