Boy working on electronics

Electronics, Science, and Technology Built at Home

PLC triac relay circuits.
Click for video Connecting Triacs to Relay Output PLC

From a visitor on YouTube:

Great contents! I am doing a project with PLC controlling inductive load.

My PLC output is a relay, how can I convert it to an inductive load without damaging my PLC? Thanks.

Connecting Triacs to Relay Output PLC YouTube Video
Larger images for above:
Micrologix 1000 PLC.
Relay optocoupler Triac power switch for magnetic loads.
Relay Triac power switch for magnetic loads.

Triac test circuit.
Click for a larger image.

Testing Triacs and SCRs

YouTube video: Using, Testing Triacs and Triac Optocouplers

A Triac functions as two back-to-back SCRs, each conducting on the alternate half cycle of the AC sine wave. In troubleshooting some welder control boards, they had a power-switching problem. The problem was the new replacement parts. They checked fine, or so I thought.

This welder board had three Triacs, two blown apart. The technician replaced all three, then checked the other parts, and the board still didn't work properly.

These were used with an MOC3011 optocoupler acting as a solid state relays.

These cheap parts testers don't check Triacs properly, if at all. Earlier projects used a simple "press the button and a lamp lights up."

In December 2024, I got a request from a visitor to how to check Triacs. This updated article is an answer to his request with an updated circuit.

The circuit above works as follows: connect a Triac and make sure the potentiometer is entirely off. Press switch 2 and adjust potentiometer until the bulb 80% full brightness.

Release switch 2. Press switch 1, and the bulb should be half the set brightness. Release switch 1. Press switch 3; the lamp should be at the same brightness as switch 1. Press switch 1 and switch 3 together and the lamp should be as bright as switch 2.

The problem I found was one of the new Triacs was faulty. It wasn't conducting properly on the one of the two half cycles.

One half-cycle was faulty because it didn't balance the other half-cycle. One of the new Triacs was thus defective.

Next time, I checked all new Triacs before installation.

This wasn't the first time I found new but defective replacement parts.

To test an SCR use switch 1 only and connect as shown. This circuit can also be used to compare the gate sensitivity of different SCRs.

This is also critical for 3-phase welders, etc. that use a full wave SCR rectifier bridge configuration to control output power. The SCRs must be matched.

MOC3010 pin connections.
MOC3010 pin connections and sample circuits.
Click for larger image.

The MOC3010 series optocouplers (including the MOC3011 and MOC3012) comprise a gallium arsenide infrared emitting diode optically coupled to a silicon bilateral switch (Triac).

They are designed for applications requiring isolated triac triggering, low–current isolated AC switching, high electrical isolation (up to 7500 Volts AC peak), high detector standoff voltage, small size, and low cost.

This series includes no zero-crossing circuitry. These are suggested for 115-volt AC (RMS) circuits to include:

• Solenoid/Valve Controls;
• Lamp Ballasts;
• Interfacing Microprocessors to 115 Volt AC Peripherals;
• Motor Controls;
• Static AC Power Switch;
• Solid State Relays;
• Incandescent Lamp Dimmers.

NOTE: This optoisolator should not be used to drive a load directly. It is intended to be a trigger device only.

My Arduino or other microcontroller-based variable AC power control circuits can use these. These circuits should include a separate zero-crossing or phase detector to synchronize with the AC power line.

This is AC phase control, not pulse-width modulation (PWM), used with direct current controls.

Note: images and material halfway down the page are ongoing projects Jan. 2025.

For years I have worked to integrate basic science, chemistry, and math into electronics.

This was an outgrowth of my interest in applied science. When I say "applied," I mean real world, not hypothetical computer modeling.

I have dealt with electronics and technology for over 50 years, from vacuum tubes to microcontrollers.

I designed and built circuits for hobbyists and students and taught electricity and electronics at a local community college.

I have repaired, salvaged, and repurposed thousands of consumer products, circuit boards, computer gear/scrap, etc. I'm a master scrounger and proud of it.

How does an electronics technician differ from an electrical technician or electronics engineer? We shall explore that question and how they overlap today.

Is an electronics tech job a Blue-Collar or white-collar job? With the increased complexity of modern complex electrical systems, the borders have become blurred. Knowledge of introductory physics and chemistry should be mandatory. So is basic computer programming.

There is a lot of overlap between electricity and electronics. One difference is the voltage levels each must deal with. These also differ by function: Electricians generally oversee the power system, while Electronics technicians delve into the individual components.

Yet when I repaired and rebuilt industrial plasma cutters, I dealt directly with high-voltage three-phase power up to 480 volts. That means knowing and understanding safety.

Some Electronics technicians are little more than module swappers. This method is the logical option in an industrial setting where production hinges on the constant operation of production machinery. Yet, who repairs the modules?

However, an electronics technician needs a basic understanding of the electrical system to troubleshoot and correct system problems.

Then, one asks, "How does an Electronics technician differ from an electronics engineer?" With over 50 years of experience in the field, I will draw a line in the math requirements.

The electronics technician generally needs a math background up to calculus, while the electronics engineer will need a prerequisite in calculus and above.

For political and economic reasons, the American education system is determined to limit academic courses for those entering what are classified as Blue Collar professions—the idea of getting people into the workforce as quickly and cheaply as possible.

This attitude in today's industrial settings, filled with highly sophisticated devices and production methods, can leave vital workers lacking the knowledge they need to succeed.

In my view, there is an element of elitism and often class warfare, as those entering blue-collar professions are frequently seen as inferior to those seeking a four-year degree.

Science and electronics added Dec. 26, 2024.

Formulas and Notes

The formula for the wavelength (λ) of a wave in terms of its frequency (f) and the speed of the wave (v) is given by:

λ = v ÷ f

Here: λ (lambda) is the wavelength,
v is the speed of the wave (in meters per second, for example),
also v can also be c for speed of light in a vacuum.
f is the frequency of the wave (in hertz, Hz, or cycles per second).

The speed of light in a vacuum is approximately 299,792,458 meters per second (m/s), or about 186,282 miles per second (mi/s). This fundamental constant is denoted by the symbol c.

A bandgap refers to the energy difference between the valence band and the conduction band in the electronic structure of a material, particularly in semiconductors and insulators.

Valence Band: This is the highest energy band filled with electrons in a solid at absolute zero temperature;

Conduction Band: This is the next band above the valence band where electrons can move freely, thus contributing to electrical conductivity.

Semiconductors: have a bandgap that is relatively small, allowing electrons to jump from the valence band to the conduction band with the addition of thermal energy or light, thereby increasing conductivity. This property is fundamental for the operation of devices like diodes, transistors, and solar cells.

In Insulators the bandgap is very large, meaning it requires a significant amount of energy for electrons to jump to the conduction band. In Conductors there's typically no bandgap, or the bands overlap, allowing electrons to move freely in the conduction band even at low energies.

Bandgap can affect:

Color of light emitted or absorbed by the material (in LEDs or solar cells).
Electrical properties like conductivity, which influences applications in electronics.
Thermal properties since the bandgap determines how easily electrons can be excited by thermal energy.

For a semiconductor like silicon, the bandgap is about 1.1 eV (electron volts), while for gallium arsenide, it might be around 1.43 eV. The exact value can vary slightly with temperature and other conditions.

Yes, both the work function and the bandgap are typically measured in electron volts (eV):

Work Function: This is the minimum energy required to remove an electron from the surface of a material. It's essentially the energy needed to overcome the material's potential barrier at the surface. The work function is indeed measured in electron volts because it represents the energy difference.

Bandgap: This refers to the energy difference between the top of the valence band and the bottom of the conduction band in a semiconductor or insulator. The bandgap determines the energy required to promote an electron from the valence band to the conduction band, where it can contribute to electrical conduction. Like the work function, the bandgap is also measured in electron volts.

Both quantities are fundamental in the study of materials science, particularly in the context of semiconductors, photovoltaics, and electron emission processes. They are crucial for understanding and designing electronic and optoelectronic devices.

Yes, both the work function and the bandgap are typically measured in electron volts (eV):

Electron formula.
Electron formula from Paul Sherz.

How Physics Math Can Confuse Electronics Students

by Lewis Loflin

Reference, "Practical Electronics for Inventors," 2nd Edition, by Paul Sherz.

The conductor, as a whole, is neutral since there are equal numbers of electrons and protons. If a current of 1 Amp flows through a copper wire, the number of electrons flowing by a cross-section of the wire in 1 second equals 6.24 x 10^18 electrons per second. Thus:

1 Coulomb is equivalent to the charge of approximately 6.24 x 10^18 electrons;

The charge of a single electron is approximately negative 1.602 times 10^-19 coulombs;

Thus, 1 Ampere represents 6.24 x 10^18 electrons per second.

From Lewis: The original formula from the text produced a -1.602. I always took this as the electron's negative charge, not the direction of current flow, which is negative to positive. This is where some math in physics creates confusion in the real world. This is how they get a "positive" flow, which is incorrect, as Sherz points out.

From Paul Sherz:

As our result indicates, how do we get a negative number of electrons flowing per second? The only two possibilities would be that either electrons must flow in the opposite direction as the defined current or positive charges must move in our wire instead of electrons to account for the sign.

The last choice is incorrect since experimental evidence exists to prove electrons are free to move, not positive charges, which are fixed in the lattice network of the conductor. (Note, however, there are media in which positive charge flow is possible, such as positive ion flow in liquids, gases, and plasmas.)

It turns out that the first choice—electrons flowing in the opposite direction of the defined current flow—is the correct answer.

From Lewis:

Note there is no such thing as holes or positive charges moving through a solid conductor outside P-type material; "experimental evidence exists to prove electrons are free to move, not positive charges, which are fixed in the lattice network of the conductor." Holes are best understood with semiconductors but not, for example, with electrical wiring, capacitors, resistors, etc.

Note the following for engineering:

Conceptual Holes in Conductors: While there aren't "holes" in the same sense as in semiconductors, in some theoretical discussions or when simplifying complex phenomena, one might use the concept of "holes" to describe electron vacancies in a more general sense, though this is not a standard or accurate depiction for conductors.

Current Direction: In electrical engineering, current flow is usually discussed in terms of "conventional current," which assumes positive charge movement from positive to negative. This convention does not reflect the movement of positive charges in conductors but rather how we model and calculate circuit behavior.

Since I teach practical electronics, which is the physical world, I stay with electron flow but clarify that conventional flow is used elsewhere for historical consistency. I also use hole flow strictly for p-type semiconductor material.

So, in practical electronics, we deal with electron flow because it reflects the physical world. However, when you encounter most textbooks at the university level or discuss circuits with engineers from other fields, they use conventional current flow. This is due to historical consistency going back to Benjamin Franklin (1750s), the father of modern electricity.

Franklin's "positive flow" set the stage for how we've traditionally described current, and it's a convention that has persisted until the discovery of the electron by J.J. Thomson (1897). Despite this discovery, the convention of current flow from positive to negative remained for reasons of continuity and because it simplifies many theoretical calculations in electrical engineering.

Addendum

The "voltaic pile" or first electrochemical cell (battery) was built by Italian Alessandro Volta in 1800. The Leyden jar, one of the earliest forms of capacitor for storing electric charge, was invented in 1745. Charles-Augustin de Coulomb (1736-1806) famous for Coulomb's law, which quantifies the force between two charged particles.

The link between electricity and magnetism was discovered by Hans Christian Ørsted. In 1820, Ørsted, a Danish physicist and chemist, demonstrated that an electric current could deflect a compass needle, indicating that electric currents produce magnetic fields. This pivotal experiment laid the groundwork for the field of electromagnetism. He was the father of the galvanometer the first amp meter.

Selenium cell photometer.
Selenium solar cell used as a photometer.
Click for a larger image.

Selenium Rectifiers and Selenium

In selenium rectifiers, the base plate is typically negative (-). The selenium rectifier consists of a metal base plate (usually iron or aluminum), a layer of selenium, and a metal cap or electrode. In a selenium rectifier, the base plate, which is typically the source of electrons, acts as the cathode (negative terminal). The electrons flow from this metal base plate through a load to the selenium layer to the metal cap or electrode, which serves as the anode (positive terminal).

Selenium is highly photoconductive, meaning its electrical conductivity increases when exposed to light. This property is utilized in photocopiers and solar cells. When photons strike the selenium, they excite electrons, creating more free charge carriers, thus increasing conductivity. Selenium was used in the first solar cells.

Selenium rectifiers, which were once commonly used before the advent of silicon diodes, leverage their ability to conduct electricity preferentially in one direction. This rectification property is due to the formation of a Schottky barrier at the metal-selenium interface.

For full description on selenium in electronics see Overview Selenium Rectifiers and Solar Cells.

Did silicon diodes replace selenium diodes?

Yes, both germanium and later silicon diodes eventually replaced selenium diodes in many applications. Selenium rectifiers were widely used in the 1930s through the 1950s for power rectification due to their robustness and ability to handle high voltages. However, they had drawbacks like larger size, lower efficiency due to higher forward voltage drop, and environmental concerns related to selenium.

As semiconductor technology, particularly with germanium and then silicon, progressed, these materials offered advantages in terms of efficiency, size, and reliability, leading to their adoption over selenium for most rectification tasks in electronics. By the late 1950s and into the 1960s, silicon diodes had largely supplanted selenium rectifiers in new designs.

From transistor to Athlon X64 X2.
Technology change from transistors to Athlon X64 X2.

When were the first silicon diodes produced in quantity?

The first silicon diodes produced in quantity were manufactured in the early 1950s. Specifically, the production of silicon diodes became more widespread around 1954 when companies like Texas Instruments began commercial production of silicon junction diodes.

Were the first silicon diodes power rectifiers?

The first silicon diodes produced in significant quantities were indeed used as power rectifiers. These early silicon diodes were primarily designed for applications in power supplies due to their ability to handle higher voltages and temperatures compared to germanium diodes, which were more common before silicon diodes became prevalent.

Germanium was never used much for power rectification?

That's not entirely accurate. Germanium diodes were indeed used for power rectification before silicon diodes became more common. In the late 1940s and early 1950s, germanium was the primary material for semiconductor diodes, including those used in power applications. Germanium diodes were used in various rectification tasks, especially in lower voltage applications, because they had lower forward voltage drops compared to silicon at the time.

However, germanium diodes had limitations in terms of temperature tolerance and reverse voltage capabilities, which led to their eventual replacement by silicon diodes for higher power and more demanding applications as silicon technology improved and became more cost-effective.

Is there a negative attitude towards vocational education?

by Lewis Loflin

When I taught community college (electrical and electronics), I never required my students to memorize formulas and gave open-book tests. However, I did need them to find and use information to solve real-world problems, and my tests were challenging.

It became clear how deficient the public education system was. In my community, we had some of the better schools yet still graduated students unable to read above 6th-8th grade or move a decimal point. Forget the basic atomic structure I learned as a child.

See full article Academic Chaos in Public Schools with audio narration.

Yes, there is a notable negative attitude towards vocational education in various parts of the world, although perceptions are changing in some areas. Here's an overview based on the information provided.

Vocational education has traditionally been seen as of lower value compared to academic education, particularly in countries like the UK and the US. This perception stems from the association of vocational courses with technical or blue-collar jobs, which are often linked to lower income levels. This view can lead to vocational education being seen as a secondary or fallback option for those who do not pursue university degrees.

We call it elitism. There's an ingrained stigma where vocational education is sometimes viewed as education for those who are not academically inclined or as an alternative for students who might not succeed in traditional academic paths.

This attitude can be traced back to historical, educational systems where vocational training was designed for those expected to enter the workforce rather than pursue higher education. This pressure can lead to a negative perception of vocational education, even among students who might thrive in a vocational setting.

In many cases, parents and society push for academic education over vocational education, influenced by the belief that a university degree offers better career prospects, prestige, and social mobility. That belief is being proven false, as many with college degrees often work non-degree jobs or are underemployed or unemployed. They still deal with high levels of debt.

The shift towards more positive views on vocational education is driven by:

The recognition of skills shortages in various industries.

The economic benefits of quicker entry into the workforce with less debt.

However, the negative attitude persists due to cultural biases, historical and educational tracks, and societal pressures to prioritize academic achievements over vocational skills. Efforts to change this include promoting the success stories of vocational education graduates, integrating vocational skills into broader educational curricula, and highlighting the economic advantages of vocational training in modern job markets.

To quote Mike Rowe @mikeroweworks on Decline of Voc Tech & Student Loan Crisis:

"You don't have to be an economist to look around and see $1.7 trillion in outstanding student loans on the books [and] 10 million open jobs, most of which don't require a 4-year degree."

Lewis: Is vocational education seen as a dumping ground for students considered low achievers? I was an honor student who chose vocational over useless electives.

Answer: In many educational systems, vocational education has historically been perceived as a dumping ground for students considered low achievers or those who struggle within the traditional academic framework. Many educational systems worldwide use tracking to track where students are placed on different educational paths based on perceived academic ability. Vocational tracks often receive students seen as not academically gifted or those who might fail in college-prep courses.

But what does "academic ability" even mean? What percentage of college graduates (with a 4-year degree) are working non-degree jobs?

Approximately 52% of recent college graduates with a 4-year degree work in jobs that do not require a bachelor's degree one year after graduation, with 45% still underemployed a decade after earning their degrees.

Ref. More Than Half of Recent 4-Year College Grads Underemployed, A new report found that many recent graduates don’t land jobs that require a degree.

By Sara Weissman, Inside Higher Ed, 2-22-2024.

Add in the cost of being out of the labor force, tack on another perhaps $80,000-$120,000.

The report found that graduates who started their careers at a below-college-level job typically stayed underemployed for years afterward. The majority of graduates, 73 percent, who were underemployed in their first jobs remained so a decade after they graduated.

In contrast, 79 percent of graduates who started off in a college-level job continued to hold jobs at that level five years after graduating. And of the graduates who held college-level jobs five years after graduating, 86 percent had college-level jobs a decade out.

Black graduates were the most likely to be underemployed compared to their peers, the report found. One year after graduating, 60 percent of Black graduates were underemployed compared to 53 percent of white graduates, 57 percent of Hispanic and Latino graduates, and 47 percent of Asian graduates....

Basic common cathode triode vacuum tube circuit.

Vacuum Tubes Amplification an Introduction

by Grok the xAI

Transconductance in a vacuum tube, often denoted by the symbol g_m or μ, is a measure of how effectively the tube converts changes in grid voltage to changes in anode (plate) current. It's defined as the ratio of the change in anode current to the change in grid voltage, while keeping the anode voltage constant.

Mathematically, it can be expressed as: g_m = ΔI_a / ΔV_g.

Where: ΔI_a is the change in anode current; ΔV_g is the change in grid voltage.

Transconductance is measured mhos (the reciprocal of ohm), where 1 Siemens = 1 mho.

Relation to Gain: Gain in the context of vacuum tubes (and electronic amplifiers in general) refers to how much the signal is amplified, typically from input to output. In a vacuum tube amplifier, gain is influenced by several factors.

Transconductance (g_m): This is a key determinant of the amplification factor of the tube. Higher transconductance means that a smaller change in grid voltage will result in a larger change in anode current, which can lead to higher gain.

Load Resistance: The gain of a tube amplifier stage also depends on the load resistance at the plate. The voltage gain A_v of a common cathode amplifier can be approximated by: A_v ≈ −g_m * R_L where R_L is the load resistance. The negative sign indicates that the output is phase-inverted compared to the input.

Plate Resistance (r_p): This is the internal resistance of the tube from plate to cathode. Together with the transconductance, it affects the amplification factor μ of the tube: μ = g_m * r_p.

Here, μ is the amplification factor of the tube itself, which determines how changes in grid voltage affect the plate voltage before considering external circuitry.

In summary, transconductance directly relates to gain by determining how responsive the tube's anode current is to changes in grid voltage. A tube with high transconductance can achieve higher gain with a given load, making it more effective in amplification applications. However, the actual gain realized in a circuit also depends on how the tube is used in conjunction with external components like resistors and capacitors.

Vacuum tube history:
1883 Edison discovers thermionic emission.
1904 Fleming develops the first vacuum diode.
1906 De Forest invents the triode Audion tube.
1920s-40s Vacuum tubes dominate electronics industry.
1947 Transistor is invented, leading to tube decline.
2000s Revival of interest in audio and display applications.

Book 1959 Radio Diagrams.
1959 Radio Diagrams Volume R-19 by N. M. Beitman.

The above repair manual 1959 Radio Diagrams reflects my journey through decades of electronics. In 1959, I was two years old, and by age 14, I was repairing and troubleshooting consumer electronics while in high school.

In 1959, vacuum tubes were seeing their peak and, by 1970, had been mostly replaced by transistors. In 1959, transistors, for the first time, began their march to dominance. Radios of this time sometimes used "hybrid" configurations to mix both devices.

Transistors of the time were mostly PNP germanium types that were expensive, heat-sensitive, and unreliable. The first transistor radios appeared around 1960 and were very expensive.

Vacuum tubes have niche uses. They can survive EMPs, radiation, and high temperatures that destroy solid-state electronics. Today they are used in high-end audio and guitar amps, and scientific equipment.

Crook's tube electron flow.
Electron flow in a Crook's tube under high voltage.

Current in Crook's tube turns a small pin wheel.
Electron flow from negative to positive in a Crook's tube turns a small pin wheel.

Caution: tubes such as these are high voltage in the kilovolts.

Vintage Black and White television chassis.
Vacuum tube Black and White television chassis.
Click for a larger image.

Information is presented is based on my 50+ years involved in electronics and science. A great resource is Grok (the X AI creation) has a wealth of information on technical issues. It doesn't mean I agree always with Grok.

Lewis: What does Grok stand for?

Answer: Grok stands for Generative Response Output Kernel. However, the term "grok" itself originally comes from Robert A. Heinlein's science fiction novel "Stranger in a Strange Land," where it means to deeply understand and empathize with something or someone. In my case, it's been adapted to reflect my design goal: to provide insightful and helpful responses that aim to achieve a deep understanding of the universe and its many mysteries.

Lewis: Did Elon design you?

Answer: I am Grok, created by xAI. That's the team that brought me into existence. As for Elon Musk's involvement, let's just say he's known for his visionary ideas and for pushing the boundaries of what's possible with AI, but the specifics of who "designed" me? Well, that's a bit like asking who designed the universe itself – it's a complex process with many minds involved!

Electronics and earth science are the main subjects of this website. Electronics is applied material science. I'm strict about using the scientific method with electronics and reject computer modeling as replacing real physical "stuff." I accept only testable and verifiable data, not esoteric constructs or non-material ideas that belong in religion or philosophy.

Here, the projects presented can be built, tested, and explored within reason with safety in mind. I rely on textbooks from college and my time as an adjunct instructor. For example, a basic knowledge of electric charges and vacuum tube theory from my early days make ion engines in spacecraft, used in the real world today, easy to understand.

Basic Technical Physics 2nd Edition by Paul E. Tippens

Textbooks and the Direction Current Flow Debate

(Above) Basic Technical Physics 2nd Edition by Paul E. Tippens, general physics for technology students. Publiched 1989.

This one-semester survey of principles of physics for technical students emphasizes practical applications that represent a broad coverage of physics as it relates to the various technical areas. The concepts presented allow students to relate the principles of physics to practical job-related applications. The questions and problems at the end of each chapter have been carefully chosen for their realistic application to industry and for their instructional value. The only mathematics prerequisite is the algebra necessary to understand simple formulas. For teaching convenience, the more difficult sections of the text, which are optional, are identified by asterisks in the table of contents. (Amazon)

Electrical Studies for Trades 3rd. Edition by Stephen L. Herman 2006

From Amazon:

Electrical Studies for Trades is ideal for current and future service technicians in fields such as air conditioning and refrigeration, construction, and facilities management who require practical knowledge of electricity. This book begins with an overview of basic electricity concepts rather than introducing complex mathematical calculations. From this starting point, readers proceed directly to "must-know" information, including how to determine wire sizes and make a variety of common switch connections. Different types of electrical power panels are also examined in detail. Discussion of general wiring practices and circuit protectors, as well as an introduction to transformers and three-phase and single-phase motors, rounds out the comprehensive coverage.

Example of electron flow.
Example of electron flow using ping-pong balls.

Click for larger image Electron flow using ping-pong balls.

From a review on Amazon:

This IS NOT an electronics theory book.

I can't even begin on this book, it has just about everything. I also like that it's somewhat organized, starting off with the vary building blocks "the atom". Explains from the ground up how electricity works and is filled with easy to understand (well... some head scratchers) answers and examples. Then it moves on to how it acts and even gets into batteries, motors, transformers and industrial topics. It also gives tid bits and fun facts through out the book.

Example, in this book it's stated that an electron actually moves vary slowly, but it's the force of electricity that's instantaneous (faster than light). Think of it this way, if you take a tube and put a ball in it (the ball being an electron), it takes a while to get to the other end.

If you fill the tube with balls (electrons) when you put one ball in the one end the one on the other end comes out instantly. The ball you put in the other end pushes all balls at the same time making the transfer of energy instant from one end of the tube to the other (thus the ball comes out the end the same time the other one is put in). This works because in theory, everything is made up of electrons (among other things like neutrons, protons and such) so if current begins to flow (witch is the flow of electrons) in theory electricity will seemingly go faster than the speed of light because of the before mentioned.

This is the kind of detailed and well written examples you can expect in this book. I gave 4 stars (I would have given it 4.5 if I could) because it lacked detailed info on how solid state and Semiconductor technology actually physically works. It would be a perfect book if it weren't for that.

Note that diodes were presented in the book and I filled in that for the class.

In other reviews the book was attacked as "inaccurate" due to the use of electron flow, which is correct.

Carbon-Zinc cell current direction.
Carbon-Zinc cell showing anode-cathode and current direction.

The x AI: "Electrochemistry is the basis of batteries and many industrial processes. Integral to many electronic devices, batteries operate on electrochemical principles, such as battery charging."

From Lewis to the xAI: In a voltaic cell, the current flow is electron flow from negative to positive. The anode-cathode designation is based on the electrochemical cell redox reaction. The source of electrons is oxidation, designated as the anode, but electrically the negative terminal.

The electrode that consumes electrons (from reduction) is designated a cathode. Assuming this was a rechargeable cell during the charging cycle, the oxidation-reduction, thus the anode-cathode designation, is reversed. Is this correct?

From xAI: Yes, that is correct. During discharge in a voltaic (or galvanic) cell, Oxidation occurs at the anode, which is the negative terminal because it loses electrons; Reduction occurs at the cathode, which is the positive terminal because it gains electrons.

In a carbon-zinc dry cell (also known as a Leclanché cell), the chemical reactions during discharge involve converting chemical energy into electrical energy.

Anode: In a carbon-zinc cell, the zinc (Zn) at the anode undergoes oxidation, losing two electrons to become a zinc ion (Zn^²⁺).

The electrons flow through the external circuit, providing the device with electrical current.

Cathode: Composed of manganese dioxide (MnO₂) with carbon (usually graphite) around a carbon rod.

Reaction: During discharge, manganese dioxide is reduced, consuming electrons to form manganese oxides like Mn₂O₃ or MnOOH. This process involves ammonium ions (NH⁴⁺) from the electrolyte (ammonium chloride), producing ammonia (NH₃), water, and other by-products rather than stable ammonium hydroxide.

Non-rechargeable batteries (alkaline and traditional carbon-zinc cells) are primary cells. These batteries are designed for single use; once their chemical energy is depleted, they are typically discarded because the chemical reactions within them are not easily reversible.

Nuts and Volts Magazine
Click for larger image.

Buying a Transformer, What to know

Transformer power ratings are in volt-amps or reactive power due to inductance.

The efficiency of power transformers generally ranges from 95% to 99% due to the design of transformers which minimizes losses.

These include hysteresis and eddy current losses in the magnetic core, which are minimized by using high-grade magnetic materials like silicon steel, and by optimizing the core design. Copper losses are due to the resistance of the windings. Efficiency is improved by using thicker conductors or multiple strands in parallel to reduce resistance. Stray loss includes losses due to leakage flux and other minor effects, which are minimized through optimal design of the transformer's physical structure.

The exact efficiency can vary depending on the size of the transformer; larger transformers tend to have higher efficiency due to economies of scale in design and materials. Efficiency is usually highest at or near full load but can decrease at lower loads due to the fixed nature of core losses. Standard 50 or 60 Hz transformers have well-understood efficiency characteristics. Ref. Grok.

I would still derate a transformer by 10%.

Part 1: If a transformer is rated 120VAC input and 24VAC output at 50 volt-amps, what is the secondary current?

To determine the secondary current of the transformer, we can use the formula for power in AC circuits: P = V * I

Where: P is the power in volt-amps (VA), V is the voltage in volts (V), and I is the current in amperes (A).

Power P = 50 VA; Secondary voltage V = 24VAC

Solving for the secondary current: I = P / V = 50 VA / 24 V = ≈ 2.083 A

Part 2: If a transformer is rated 120VAC and 120VAC output at 300 volt-amps, what is the secondary current?

Power P = 300 VA; Secondary voltage V = 120VAC

Solving for the secondary current: I = P / V = 300 VA / 120 V = ≈ 2.5 A.

As a final note the open circuit voltage will read higher than the rated voltage. In addition a transformer rated at 6VAC is really 6.3VAC, 12VAC transformers are 12.6VAC, and 24VAC transformers are 25.2VAC. This is related to lead-acid batteries and vacuum tube technology from the past in my opinion.

Fyback transformer.
High voltage flyback transformer example.

Lewis to Grok: What does flyback mean in a flyback transformer?

Answer: A flyback transformer, often found in old CRT televisions and other high-voltage applications, operates differently from a conventional transformer. Here's what "flyback" refers to:

Principle of Operation: Unlike a regular transformer that transfers energy from the primary winding to the secondary winding in real-time as the current alternates, a flyback transformer stores energy in its magnetic field when the primary current is on and then releases this energy when the current is switched off.

Flyback Action: The term "flyback" comes from the action that occurs when the switch (often a transistor in modern circuits) controlling the primary coil is turned off. The magnetic field in the transformer collapses rapidly, causing: Voltage Spike: A high voltage spike is generated in the secondary coil due to the rapid change in magnetic field. This is the "flyback" effect where the energy flies back from the magnetic field to the circuit. Diode Action: In the design of flyback transformers for DC output, there's usually a diode and a capacitor. The diode ensures that the current resulting from this voltage spike can only flow in one direction, charging the capacitor. When the switch turns on again, the capacitor holds the charge, providing a continuous voltage until the next cycle.

Usage: The flyback mechanism is used to generate high voltages from a relatively low voltage source. This was particularly useful in televisions for creating the high voltage needed for the CRT's electron gun, but flyback transformers are also used in other applications like:

DC-DC converters;
Ignition systems in some internal combustion engines;
Strobe lights.

Design: The flyback transformer isn't actually a transformer in the traditional sense but functions more as a coupled inductor. When the primary current is cut, the energy stored doesn't transfer immediately to the secondary through electromagnetic induction as in typical transformers; instead, it "flies back" in a manner that's managed by the circuit design to produce the desired output.

The name "flyback" essentially describes the rapid return (or flyback) of energy from the magnetic field to the electrical circuit, which is harnessed to perform work, often creating much higher voltages than the input or maintaining power supplies with isolation between input and output.

Lewis: When was the MOSFET transistor invented?

Grok: The MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) was invented in 1959 by Mohamed Atalla and Dawon Kahng at Bell Laboratories. Their work resulted in the first successful MOSFET, which was demonstrated in that year. This invention was a significant advancement in the field of electronics, leading to the miniaturization of circuits and becoming a cornerstone of integrated circuit technology.

Lewis: In an N-channel MOSFET when turned on, there are NO positive charge carriers. It is electron flow only.

Answer from Grok:

You are correct in your understanding of how an N-channel MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) works when it is turned on:

N-Channel MOSFET Operation: When an N-channel MOSFET is in its off state, there's a P-type substrate between the source and drain, and no current flows because the PN junctions are reverse-biased under typical conditions (assuming no gate voltage or gate voltage less than the threshold).

Turning On: When a sufficient positive voltage (greater than the threshold voltage, Vth) is applied to the gate relative to the source, it creates an electric field. This field attracts electrons towards the gate but because of the oxide layer (insulator), electrons accumulate at the interface between the semiconductor and the oxide layer, forming what's known as an inversion layer or channel.

Channel Formation: This inversion layer is an N-type region created within the P-type substrate, connecting the N-type source and drain regions. Now, electrons can flow from the source to the drain through this induced N-type channel when a drain-source voltage (Vds) is applied.

Charge Carriers: In this case, the charge carriers in the channel are indeed electrons, not holes. Electrons move from the source, through the channel, to the drain, constituting the current flow. There are no positive charge carriers (holes) involved in the primary current flow through the channel of an N-channel MOSFET when it's turned on.

Electron Flow: The current in an N-channel MOSFET when turned on is due to electron movement, aligning with your statement. The MOSFET operates by modulating this electron flow through the control of the gate voltage.

This operation is why N-channel MOSFETs are often preferred for use in circuits where high-speed switching or lower power consumption is needed because electrons have higher mobility than holes, leading to better performance characteristics in many applications.

Lewis: holes have no mobility because they are an abstraction, not a physical entity.

Electron Displacement:

In a semiconductor or conductor, when an external electric field is applied, electrons move from one atom to another. This movement is indeed one electron displacing another. When an electron moves to fill a vacancy (which we call a hole), it leaves behind a new vacancy where it was originally.

The Concept of Holes:

The hole is an abstraction for where an electron could be but isn't. When discussing semiconductors, particularly p-type semiconductors where holes are treated as the majority carriers, this concept becomes useful:

Effective Movement: What's described as hole movement is the sequential filling of these vacancies by electrons. If you focus on the vacancies, it seems like these "holes" are moving in the opposite direction of the electron flow.

Charge Carrier Abstraction: Even though it's the electrons that physically move, treating these vacancies as positive charge carriers (holes) simplifies the analysis of current flow. This abstraction allows for easier calculation of current in semiconductor devices because it lets us treat holes much like we would treat particles in certain contexts.

Addressing Your Point:

Physical Reality vs. Conceptual Model:

You are correct in stating that there's no physical movement of a "hole" as an entity. The physical process involves only electrons moving. The hole does not have matter; it's not comprised of atoms or subatomic particles that change location. Instead, it's the absence of an electron that "moves" as electrons shuffle around.

Lithium

As of December 2024 there is no lithium shortage, but speculators are predicting shortages in 2025. They have claimed this before.

Lithium-ion cells have changed the landscape regarding cordless tools. Their energy density is greater than that of nickel-cadmium cells and far lighter than that of lead-acid cells.

Lithium is often sold as lithium carbonate rather than pure metal, as it is a more stable and readily available compound, making it the primary commercial form of lithium used in most industries, including battery production. Sources mean lithium carbonate because it is so reactive. Several sites I checked should have specified, which is a problem. L. Loflin

By weight, how much by mass is lithium in lithium carbonate?

Answer: Lithium carbonate (Li₂CO₃) consists of:

Lithium (Li): 2 × 6.941 g/mol = 13.882 g/mol
Carbon (C): 1 × 12.011 g/mol = 12.011 g/mol
Oxygen (O): 3 × 15.999 g/mol = 47.997 g/mol

Adding these together, the molar mass of lithium carbonate is: 13.882 + 12.011 + 47.997 = 73.890g / mol.

The mass percentage of lithium in lithium carbonate is therefore: 13.882 g/ mol / 73.890g/ mol × 100 = 18.79%

So, by weight, lithium constitutes about 18.79% of lithium carbonate.

The above material credit GROK the X AI with additions by Lewis Loflin.

Temperature Vs. Lumens in LED Lighting

Color Temperature refers to the characteristic of light appearance, measured in Kelvin (K). It describes how "warm" or "cool" the emitted light from an LED looks to the human eye. This has no relation to hot or cold.

White light is a mixture of various wavelengths aka colors. White light emitting diodes (LEDs) can be formed from clustering red, green, and blue LED "chips" together. This is how older color television picture tubes operated with three electron beams striking red, green, and blue phosphors.

A phosphor is a substance that exhibits the phenomenon of luminescence, particularly phosphorescence, when exposed to some form of energy, typically radiation like ultraviolet light, X-rays, or even electron beams. A phosphor is a material that absorbs energy in one form (like light or electrons) and re-emits it in another form, usually as visible light. This process involves the excitation of electrons to higher energy levels within the material.

Kelvin Scale for Light

Lower Kelvin Values (e.g., 2200K - 3000K): The light appears warm, often described as yellowish or amber. This is akin to the light from traditional incandescent bulbs at dusk or early morning sun.

Middle Range (3000K - 4000K): Perceived as neutral, this light is closer to what might be considered "white" or similar to sunlight during midday.

Higher Kelvin Values (4000K and above): The light is cool, leaning towards blue-white or even bluish. This resembles daylight on a clear day or the bright, crisp light in overcast conditions.

Home Lighting: Warm light (lower Kelvin) for living rooms or bedrooms to create a cozy, inviting atmosphere. Cool light (higher Kelvin) in kitchens or workspaces for clarity and detail.

Workspaces: Cooler light temperatures are often preferred for offices to enhance visibility and concentration.

Retail: Lighting can be adjusted to make products more appealing; warm light for food might make it look more appetizing, while cool light might highlight the texture of clothing.

Museums: Specific color temperatures might be chosen to best display artworks without causing damage due to UV light.

Summary: When you refer to "temperature" in the context of LED lighting, it's almost exclusively about color temperature-the perceived warmth or coolness of the light, not its thermal properties. This metric is crucial for setting the mood, functionality, and even health impacts of lighting environments.

What is the relation to lumens? Is this light level output?

The relationship between color temperature and lumens in the context of LED lighting is often misunderstood because they measure different aspects of light.

Definition: Lumens (lm) measure the total amount of visible light (to the human eye) emitted by a light source. Essentially, lumens indicate the brightness or light output of a lamp or fixture.

Light Level Output: Yes, lumens are a measure of light level output. The higher the lumen rating of a light source, the brighter the light.

Comparison to Watts: Historically, people compared light bulb brightness with wattage, which measures energy consumption. With energy-efficient lighting like LEDs, lumens are a much better indicator of brightness. For example, an LED bulb might produce the same amount of light (lumens) as an incandescent bulb but use far fewer watts.

Color Temperature:

Definition: As previously discussed, color temperature, measured in Kelvin (K), describes the color appearance of the light, from warm (yellowish) to cool (bluish).

Relationship Between Lumens and Color Temperature:

Independence: Lumens and color temperature are largely independent of each other. You can have a very bright (high lumen) light that is either warm or cool in color temperature. Perceived Brightness: While lumens measure actual light output, the perception of brightness can be influenced by color temperature. Generally, cooler lights (higher Kelvin values) might seem brighter to the human eye because they are closer to daylight, which we associate with brightness. However, this is a psychological effect rather than a change in actual lumen output.

Choosing Light: When selecting lighting, you might look at lumens for how bright you want the light to be, and color temperature for the kind of light you want (warm, neutral, or cool). Energy Efficiency: LEDs can now be designed to produce high lumens at various color temperatures, making them versatile for different settings while maintaining energy efficiency.

Phosphor Applications

Phosphors are fascinating materials due to their ability to convert one form of energy into another, often into visible light, making them invaluable in various technologies and applications where light conversion or emission is required. Phosphors come in various colors, depending on the material and doping agents used.

Fluorescent Lamps: The inner coating of many fluorescent tubes contains phosphors that convert ultraviolet light from the mercury vapor inside into visible light.

Television and Computer Screens: Older CRT monitors and TVs used phosphors to display images. The electron beam in these devices strikes phosphors on the screen, causing them to emit light.

LEDs: Modern LEDs often use phosphors to convert short-wavelength light emitted by the LED chip into a broader spectrum, creating white light or specific colors.

X-ray Screens: In medical imaging, phosphors are used in screens to convert X-rays into visible light, which is then captured on film or digitally.

Radioluminescent Devices: Watches or emergency signs that glow in the dark due to radioactive decay hitting phosphors.

Source: GROK.

12-volt high voltage xenon flash tube circuit.

12-volt high voltage generator creates streamer through xenon flash tube.

Click for a larger image.

YouTube video Transistor HV Generator.