Astable Multivibrator - Answers to Questions Vocademy - Electronics Technology 2026-09-29 | Astable Multivibrator - Answers to Questions
March 2025 Mercury Apparition and Dance with Venus Vocademy - Electronics Technology 2025-03-01 | When Mercury has its greatest elongation (greatest separation from the Sun) in the spring, it gets higher in the evening sky than usual. That's happening this year. Venus will also be getting closer to the Sun, so Venus and Mercury will be close to each other and then move toward inferior conjunction (going between the Earth and the Sun) together.Vocademy - Free Vocational Education
March 13-14, 2025 Total Lunar Eclipse Vocademy - Electronics Technology 2025-03-01 | There will be a total eclipse of the moon visible in North America and western South America on 13-14 March 2025.Vocademy - Free Vocational Education
CCDs and CMOS Imaging Devices - Solid-state Devices and Analog Circuits - Day 12, Part 6 Vocademy - Electronics Technology 2025-03-01 | CCDs and CMOS imaging devices made digital photography affordable.Vocademy - Free Vocational Education
Solid state Optoelectronic Devices - Solid-state Devices and Analog Circuits - Day 12, Part 0b Vocademy - Electronics Technology 2025-02-02 | Photoresistors, photodiodes, phototransistors, and opto-isolators.Vocademy - Free Vocational Education
Fixing My Meade Schmidt-Cassegrain Telescopes Electronics Vocademy - Electronics Technology 2025-01-30 | How I troubleshot and fixed a Meade LX200 10-inch telescope with non-functional electronics.This is a remake of the previous video by the same name but I added several clarifying graphics.Refractive Optics:youtu.be/qDGU71FQ878Reflective Optics:youtu.be/jV5EtWbYIloVocademy - Free Vocational Education
Vocademy World Headquarters Tour Vocademy - Electronics Technology 2025-01-21 | Here's why I haven't made any new videos for the last couple of weeks. I have a new dedicated studio and office.Vocademy - Free Vocational Education
Early Optoelectronic Devices - Solid-state Devices and Analog Circuits - Day 12, Part 0a Vocademy - Electronics Technology 2025-01-12 | Phototubes, photomultipliers, imagers, image intensifiers, and television camera tubes--the first optoelectronic devices.Vocademy - Free Vocational Education
January 2025 Planetary Alignment Vocademy - Electronics Technology 2025-01-09 | Social media is all abuzz about the big planetary alignment later this month. Too bad it's not happening. However, some interesting things are going on.Help make these videos and keep Vocademy free:patreon.com/vocademypaypal.me/VocEdMy astronomy site:amsky.netVocademy - Free Vocational Education
Basic Fiber Optics - Solid-state Devices and Analog Circuits - Day 12, Part 5 Vocademy - Electronics Technology 2024-12-20 | Fiber optic basicsVocademy - Free Vocational Education
CDs, DVDs and Blu-ray Discs, Part 2 - Solid-state Devices and Analog Circuits - Day 12, Part 4c Vocademy - Electronics Technology 2024-12-06 | Continuing with optical recording: how LaserDiscs, CDs, DVDs, and Blu-ray Discs are made, data encoding, writable and rewritable discs, etc., part 2.Vocademy - Free Vocational Education
CDs, DVDs and Blu-ray Discs, Part 1 - Solid-state Devices and Analog Circuits - Day 12, Part 4b Vocademy - Electronics Technology 2024-12-06 | Continuing with optical recording: how LaserDiscs, CDs, DVDs, and Blu-ray Discs are made, data encoding, writable and rewritable discs, etc., part 1.Vocademy - Free Vocational Education
LaserDisc - Solid-state Devices and Analog Circuits - Day 12, Part 4a Vocademy - Electronics Technology 2024-11-26 | LaserDisc was the granddaddy of all optical recording used today. Compact Disc, DVD and Blu-Ray are all refinements of this technology.Vocademy - Free Vocational Education
What Makes Electricity Flow in a Circle Around an Inductor Vocademy - Electronics Technology 2024-11-23 | The EtherealMechanics channel says the physics taught in universities is wrong. As an example, the presenter says that accepted classical and relativistic physics can't explain the rotational force around an inductor with a changing magnetic field.Actually, accepted classical and relativistic physics can explain this force. This video explains my take on it.Here are the other videos mentioned in this video:EtherealMechanics - Science is broken:youtu.be/5BRvwhfdfVgVocademy - Electricity, Magnetism and Special Relativity:youtu.be/Z31jsD63nsAVeritasium - How Special Relativity Makes Magnets Workyoutu.be/1TKSfAkWWN0Fermilab - Dr. Don Lincoln - How Einstein saved magnet theoryyoutu.be/d29cETVUk-0To support free vocational education at Vocademy and this channel, go to patreon.com/vocademy
A Brief History of the Discovery of Electricity - DC and AC Circuits - Day 1, Part 1 Vocademy - Electronics Technology 2024-11-16 | I made a few errors in this early video. Until I can remake it, I added some corrections to the original.Vocademy - Free Vocational Education
Optoelectronics - Laser - Solid-state Devices and Analog Circuits - Day 12, Part 3 Vocademy - Electronics Technology 2024-11-10 | Laser (Light Amplification by Stimulated Emission of Radiation) is created by manipulating the common phenomenon of stimulated emission.The thumbnail for this video shows an ultraviolet laser beam coming from the adaptive optics system of the 60-inch (1.5 meter) telescope on Palomar Mountain. The laser creates an artificial star that the adaptive optics system uses to continually align the system to eliminate atmospheric turbulence. The beam is UV (invisible to the eye), but the image was taken with a DSLR camera that had the UV filter removed. The UV light stimulates the RGB sensors to different amounts, resulting in a false orange appearance.Vocademy - Free Vocational Education
Optoelectronics - Reflective Optics - Solid-state Devices and Analog Circuits - Day 12, Part 2b Vocademy - Electronics Technology 2024-11-02 | Vocademy - Free Vocational Education
Optoelectronics - Refractive Optics - Solid-state Devices and Analog Circuits - Day 12, Part 2a Vocademy - Electronics Technology 2024-11-02 | Vocademy - Free Vocational Education
Optoelectronics - The Nature of Light - Solid-state Devices and Analog Circuits - Day 12, Part 1b Vocademy - Electronics Technology 2024-10-28 | Vocademy - Free Vocational EducationThe nature of light, part 2. Interference, diffraction, refraction and reflection.
Optoelectronics - The Nature of Light - Solid-state Devices and Analog Circuits - Day 12, Part 1a Vocademy - Electronics Technology 2024-10-27 | Vocademy - Free Vocational EducationThe wave/particle duality of light, wavelength, frequency, phase, and polarization.
Monaural and Multichannel Sound - Solid-state Devices and Analog Circuits - Day 11, Part 6 Vocademy - Electronics Technology 2024-10-17 | Vocademy - Free Vocational Education
Loudspeaker Impedance and PA Systems - Solid-state Device and Analog Circuits - Day 11, Part 5 Vocademy - Electronics Technology 2024-10-15 | Vocademy - Free Vocational Education
Loudspeaker Basics and Enclosures - Solid-state Devices and Analog Circuits - Day 11, Part 4 Vocademy - Electronics Technology 2024-10-13 | Vocademy - Free Vocational EducationWhat are loudspeakers, and how are speaker enclosures made.
Sound - Solid-state Devices and Analog Circuits - Day 11, Part 0 Vocademy - Electronics Technology 2024-10-03 | Vocademy - Free Vocational EducationThe nature of sound
Microphones - Practical Application - Solid-state Devices and Analog Circuits - Day 11, Part 3 Vocademy - Electronics Technology 2024-09-21 | Vocademy - Free Vocational EducationUsing microphones
Microphone Patterns and Stereo Recording - Solid-state Devices and Analog Circuits - Day 11, Part 2 Vocademy - Electronics Technology 2024-09-09 | Vocademy - Free Vocational EducationA Quick Look at Decibels:youtu.be/aiEI8KiuVT8
Microphone Development and Types - Solid-state Devices and Analog Circuits - Day 11, Part 1 Vocademy - Electronics Technology 2024-09-01 | Vocademy - Free Vocational EducationThis video discusses the development and types of microphones.
Revisited - Variable Duty Cycle Op-amp-based Relaxation Oscillator Vocademy - Electronics Technology 2024-07-09 | Vocademy - Free Vocational EducationRevisiting the variable duty cycle op-amp-based relaxation oscillator with the Falstad circuit simulator.
Variable Duty Cycle Op-amp-based Relaxation Oscillator Lab Vocademy - Electronics Technology 2024-07-09 | Vocademy - Free Vocational Education
Tunnel Diode Oscillators See Errata in the Description Vocademy - Electronics Technology 2024-06-17 | Vocademy - Free Vocational Education - vocademy.netErrata:I misread the oscilloscope trace I used to show the voltages and currents of the charastic curve of a tunnel diode--I misread by a factor of 10, seeing 8 mA as 80 mA. This throws off my current and impedance numbers by the same factor. This doesn't affect the explanation and would be correct for a tunnel diode that operates at the currents I mentioned. However, it turns out that the curve I misread is typical, making my numbers unrealistic. While relating this video to a real tunnel diode, decrease the currents by a factor of 10 and increase the impedances/resistances by the same factor.Circuit simulator at falstad.com:Tunnel Diode Relaxation Oscillator:falstad.com/circuit/e-tdrelax.htmlClick Circuits, Misc Devices, Tunnel Diodes, and LC Oscillator for the LC tunnel diode oscillator.Yes, I was quoting Peter Schickele at the conclusion of the video.
Clapp, Vackář, and Seiler Oscillators - Solid-state Devices and Analog Circuits - Day 6, Part 12 Vocademy - Electronics Technology 2024-06-17 | Vocademy - Free Vocational EducationThe Clapp, Vackář, and Seiler oscillators are based on the Colpitts oscillator. The Clapp oscillator adds a variable capacitor in the inductor leg of the tank circuit. This capacitor is typically about one-tenth of the combined capacitance of the two capacitors on the other leg of the tank circuit. Having a lower capacitance gives the variable capacitor a greater effect on the frequency (lower capacitance causes higher capacitive reactance).The Vackář oscillator moves the inductor out of the tank circuit and closer to the transistor's collector. This gives the Vackář oscillator greater frequency and voltage stability. The Seiler oscillator uses a capacitor network to provide positive feedback from the emitter to the base of the transistor.
Tunnel Diodes - Has Errors, See Errata in the Description Vocademy - Electronics Technology 2024-06-13 | Vocademy - Free Vocational Education - vocademy.netErrata:I misread the oscilloscope trace I used to show the voltages and currents of the charastic curve of a tunnel diode--I misread by a factor of 10, seeing 8 mA as 80 mA. This throws off my current and impedance numbers by the same factor. This doesn't affect the explanation and would be correct for a tunnel diode that operates at the currents I mentioned. However, it turns out that the curve I misread is typical, making my numbers unrealistic. While relating this video to a real tunnel diode, decrease the currents by a factor of 10 and increase the impedances/resistances by the same factor.The quantum tunneling effect causes a tunnel diode to act much like a fixed resistor of about five or six ohms when reverse-biased or below about 50 millivolts when forward-biased. Between about 50 millivolts and 300 millivolts (0.05 and 0.3 volts), assuming a germanium diode, the impedance of the tunnel diode increases exponentially as the voltage increases. This causes the current to decrease linearly as the voltage increases; the reverse of a fixed resistor. This is called the negative resistance region. Above 300 millivolts, the germanium tunnel diode acts like a regular germanium diode.The negative resistance region, along with the tunnel diode's low capacitance, can be exploited to create microwave-frequency oscillators. The tunnel diode acts like a voltage-sensitive variable resistor that provides a current inverse to the voltage of a ringing tank circuit. This current is, thus, fed into the tank circuit at the correct phase to compensate for the damping as energy is dissipated by the circuit's resistance.The "little green man" model used in this video is similar to the LGM model I use to explain the zener diode in the following video: youtu.be/RSHahPnioW0
Blocking Oscillators - Solid-state Devices and Analog Circuits - Day 6, Part 11 Vocademy - Electronics Technology 2024-05-28 | Vocademy - Free Vocational EducationThe blocking oscillator exploits circuit saturation to cause a sudden collapse of the magnetic field in the primary of a feedback transformer. This sudden collapse of the magnetic field causes the transistor base voltage to drop or reverse, blocking the transistor's operation. This desaturates the circuit and starts the cycle over.
Relaxation Oscillators - Solid-state Devices and Analog Circuits - Day 6, part 10 Vocademy - Electronics Technology 2024-05-24 | Vocademy - Free Vocational EducationRelaxation oscillators exploit a sudden change in a circuit parameter when the circuit reaches a given voltage or current. This change does not reverse until a different threshold is reached (hysteresis). In the simplest example in this video, a neon light starts to conduct when a parallel capacitor charges to about 90 volts. The conducting bulb discharges the capacitor. The bulb stops conducting at around 60 volts, allowing the capacitor to charge again. Other relaxation oscillators use different mechanisms, but the common characteristic is one voltage of current triggering a change in the circuit but a different voltage or current reversing the change. youtu.be/cwY2AOUhtLM
Crystal Oscillators - Solid-stated Devices and Analog Circuits - Day 6, Part 9 Vocademy - Electronics Technology 2024-05-18 | Vocademy - Free Vocational EducationThe transistor symbol in the schematic for a Pierce oscillator is for a PNP transistor where the 2N2222 and 2N3904 are NPN transistors. There is a link to the corrected schematic at the appropriate point in the video and here: youtu.be/SQ9_buobb9M
Armstrong Oscillator - Solid-state Devices and Analog Circuits - Day 6, Part 8 Vocademy - Electronics Technology 2024-05-09 | The Armstrong oscillator is much like a Colpits or Hartley oscillator but with a transformer providing feedback.Vocademy - Free Vocational Education
Colpits and Hartley Oscillators - Solid-state Devices and Analog Circuits - Day 6, Part 7 Vocademy - Electronics Technology 2024-04-26 | The Colpits and Hartley oscillators use a tuned circuit to determine the frequency of operation and to provide positive feedback.Vocademy - Free Vocational Education
Wien-bridge Oscillator - Solid-state Devices and Analog Circuits - Day 6, Part 6 Vocademy - Electronics Technology 2024-04-20 | The Wein-bridge oscillator is an astable multivibrator with a high-Q bandpass filter and controlled gain that produces sine waves.Vocademy - Free Vocational Education
Astable Multivibrator - Solid-state Devices and Analog Circuits - Day 6, Part 5 Vocademy - Electronics Technology 2024-04-05 | The astable multivibrator is one of the simplest oscillators. It is simply two common-emitter amplifiers where the output of the second is fed to the input of the first. Because of its high gain, it saturates and produces square waves.Here is the link to my detailed video on the astable multivibrator:youtu.be/9eRWKh7OOHwVocademy - Free Vocational Education
Oscillator Fundamentals - Solid-state Devices and Analog Circuits - Day 6, Part 4 Vocademy - Electronics Technology 2024-03-25 | This is part one of my series on electronic oscillators. In this video, we explore the fundamentals of electronic oscillators. What is oscillation? What kind of things oscillate? What are oscillators? We explore pendulums, acoustic feedback, and the phase shift oscillator. Learn More:How FOUCAULT PENDULUM Works...: youtu.be/8JxyT0edT6cWhat the Phugoid is... (I need to make a minor correction): youtu.be/9DnSG4H2UjE?How to get feedback out of choir mics: youtube.com/live/FoZoZv9IY1QEscapement Theory: youtu.be/SUuv0_gHQQsVocademy - Free Vocational Education00:00 Title and introduction01:11 What is oscillation06:40 What are oscillators08:49 Key requirements11:54 Sine waves and harmonics20:20 Feedback in an auditorium29:33 The phase shift oscillator40:10 Coming up40:34 Epilog
Prelude to Oscillators Vocademy - Electronics Technology 2024-03-17 | Vocademy - Free Vocational EducationI am preparing to do a video series on oscillators. Here is a short preview of where this is taking me.
Amplifier Configurations - Solid state Devices and Analog Circuits - Day 6, Part 3 Vocademy - Electronics Technology 2024-03-10 | Vocademy - Free Vocational Education
Practical Analog Circuits - Solid-state Devices and Analog Circuits - Day 6, Part 2 Vocademy - Electronics Technology 2024-03-04 | Vocademy - Free Vocational EducationLearn electronics technology for free at vocademy.netSolid-state Devices and Analog CircuitsDay 6, Part 2Practical Analog Circuits
Math Review - Exponents and Logarithms - Solid-state Devices and Analog Circuits - Day 6, Part 1 Vocademy - Electronics Technology 2024-02-27 | Vocademy - Free Vocational EducationSolid-state Devices and Analog CircuitsDay 6, Part 1Math ReviewExponents and LogarithmsLearn electronics technology for free at vocademy.netvocademy.netsupport.vocademy.net
Linear Power Supply Teardown and Autopsy With Appearance by Dave Jones Vocademy - Electronics Technology 2024-01-10 | Vocademy - Free Vocational EducationSolid-state Devices and Analog Circuits - Day 9 SupplementalWhile working on my laser communicator, my power supply failed, and not failing to a safe condition, it put 23 volts across my laser pointer. Let's see what happened.
J-FETs Solid-state Devices - Day 5, Part 1 Vocademy - Electronics Technology 2024-01-08 | Vocademy.net - free vocational educationThe J-FET is a modification of the diode. By manipulating the width of the depletion region, by changing the gate-to-source voltage, the conductance between the drain and the source is changed.Reading assignment:http://vocademy.net/textbooks/solidstatedevices/ShowPage.php?CourseDirectory=solidstatedevices&FileName=FieldEffectTransistorsHere's the playlist for this lecture series:youtube.com/playlist?list=PLNm1_xEfhzSCIJuy-pBP7fZvwjRPXrp5CLearn electronics technology for free at Vocademy - vocademy.netHelp make these videos and free vocational education possible by pledging your support at Patreon:patreon.com/vocademyMake one-time donations at:paypal.me/rsdacademy
MOSFETs Solid-state Devices - Day 5, Part 2 Vocademy - Electronics Technology 2024-01-08 | Vocademy - Free Vocational EducationMOSFETs are a very popular transistor because of their low power consumption. This video explains their basic operation.Reading assignment: http://vocademy.net/textbooks/solidstatedevices/ShowPage.php?CourseDirectory=solidstatedevices&FileName=FieldEffectTransistorsHere's the playlist for this lecture series:youtube.com/playlist?list=PLNm1_xEfhzSCIJuy-pBP7fZvwjRPXrp5CLearn electronics technology for free at Vocademy -- vocademy.net
KVL and Induction One Last Lash at the Dead Horse Vocademy - Electronics Technology 2024-01-08 | Vocademy - free vocational educationvocademy.netInverted Realities (youtu.be/ldjIkYqV9xo) tested Dr. Walter Lewin's hypothesis using a toroidal inductor. He didn't take into account that emf acts as if it only exists inside the toroid hole and concluded that Kirchhoff's Voltage Law fails with a changing magnetic field. Applying the nature of a toroidal inductor and Kirchhoff's Voltage Law, I predicted Inverted Realities' outcome. This shows that by understanding how devices work, you can make accurate predictions and not be fooled by false premises.Here are the videos referred to in this video:Kirchhoff's Voltage Law Fails, or Does it: youtu.be/jHTT-m4_F4oWhere is the emf in a Toroidal Inductor: youtu.be/WLwoc43FoeoVoltage in a Loop is Weird: youtu.be/Bp3iw_tBdvQVocademy is a free online vocational school, and we rely on free-will donations to operate. You can be a big help for as little as $12.00 per year. Please go to our support page to see how to make a monthly pledge or a one-time donation.support.vocademy.net
Amplifier Classes - Solid-state Devices and Analog Circuits Day 7, Part 1 Vocademy - Electronics Technology 2023-12-28 | Vocademy - Free Vocational EducationAmplifiers are classified according to how many degrees of a sine wave they operate on.Video on switching regulators: youtu.be/86E3ONEJXbY
Switching Regulators - Solid-state Devices and Analog Circuits - Day 9, Part 7 Vocademy - Electronics Technology 2023-12-28 | Vocademy - Free Vocational EducationSwitching regulators are more efficient than linear regulators.
Class B Push Pull Amplifier - Solid-state Devices and Analog Circuits Day 7, Part 2 Vocademy - Electronics Technology 2023-12-25 | Vocademy - Free Vocational EducationClass B push-pull amplifiers are more efficient than Class A amplifiers.
