Great presentation! I will add that there are some nuances with inductors in a DC circuit. 1 - current in the circuit doesn't immediately rise, it rises exponentially. Once it reaches steady state, it is essentially "just a wire". 2 - When power is removed, there will be a large current spike (flyback). Also, an analogy that I particularly like, is a stream of water that is causing a heavy water wheel to move. It takes time for it to get going, and it doesn't immediately stop if the stream were to stop.
Those are great points! Particularly with the inductor, I've thought about doing another specific video for inductors (An "Intermediates of Inductors" perhaps? Need a better title) where we go over those specific things. I didn't understand the point of a flyback diode with FETs and H-bridges until I had a better intuitive understanding of inductors and how many devices and real-life appliances in my house are basically huge inductors.
In an RL circuit (resistor in series with inductor), the current rises exponentially. If an inductor is directly connected to a steady DC source the current rises linearly with time, with no limit with an ideal source and an ideal inductor. di/dt = V/L i in amperes, t in seconds, V in volts, L in henries the differential of current through an inductor with respect to time is equal to the applied voltage divided by the inductance or the rate of change of current through the inductor is equal to the applied voltage divide by the inductance
for people starting out with electronics understanding..any additional information (bringing up circuit analysis, ignoring inductors, replacing inductors, etc) can add resistance to acquiring the basic understanding of what inductors do, and why they are absolutely necessary in certain situations. Some of us arent ready to immediately apply brand new understanding to future pursuits of knowledge. Just a thought Im having as i watch this video. I like the video, and I understand you are trying to pack in as much information as possible..just a suggestion from a total noob who is trying to understand inductors at the most basic level and see real-world examples of where inductors are used and what would occur if they were not in use.
Momentum. Imagine trying to change every textbook, multimeter, video, *everything* in the world that talks about positive, negative, and conventional current? And, of course, the mental momentum of all the current electricians, technicians, and electrical engineers? I can't imagine it, personally, and that's basically why. Kinda sucks... 🤷♂️
Can you explain v=L di/dt as a supplement? I don't understand what a graph of that would look like, L is constant and if I wanted to graph that how do you see di / dt in creating v? Is di / dt linear?
We should definitely do a video specifically on this topic as it can be confusing. The general concept applies to both inductors and capacitors but we'll just focus on inductors at the moment. First, remember that for a resistor, V = IR. But that doesn't apply to inductors, the equation doesn't work. The only time there is a voltage over an inductor is if there is a *CHANGE* in current. If you've taken differential calculus, you can look at di/dt and realize that this represents a change in current in regards to a change in time (i being current, t being time) So, to know what the voltage across an inductor is at any moment in time, you need to know its inductance (L) and then multiply it by the change in current. Knowing that an inductor acts like a short in DC, you should look at the equation and have it click about why that is. In steady-state DC, the current wouldn't change, so di/dt = 0 and V = 0. If there's no voltage over the inductor, it's acting like a short. On the other end, in an AC circuit, if frequency is very high, current is trying to change direction frequently, so di/dt is very high. Thus, voltage would be very high. Things get really interesting when there are abrupt changes in current in an inductor (like unplugging a running vacuum cleaner - which is basically an inductor) as that has a large change in current, a large inductor, and ends up generating a very large voltage, which is why your plug may spark when you do that. Sorry, this is way too long for a comment but too short to really get in depth in the topic. Hopefully it is helpful in some way, though!
@@CircuitBread the explanation is helpful. It would also be great to explain inrush on motors. This is counter intuitive to me because motors seem to be big inductors so why is there an inrush? Wouldn't the inductor resist change in current and soften the ok brush current? Also I did look some more and found a few things. The di/dt nature definitely confuses me when they talk about a boost converter. I may not be writing this well, but it seems whenever they draw the voltage of the boost when the switch closes, they draw the line perfectly linear....I don't know why that is instead of a curved ramp... I'm confused with that too
@@CircuitBread I'm not an electrical engineer, but just someone with a casual interest in this subject. When you mentioned that a plug may spark, in your reply to Millax. It reminded me of my 120v induction hot plate that sparks every time I plug it in the receptacle (just when I plug it in, not when pulling the plug out). Any chance that has to do with the induction part of the hot plate, or is it just some issue in the manufacturing process? Thanks, I enjoy your videos.
There are a couple uses for inductors but, particularly as I've gotten more into ham radio recently, one of the biggest things is changing the resonant frequency of a circuit. With an AC circuit, certain frequencies can be blocked or transmitted better than others and it's dependent on the capacitor and inductor values within the circuit. This has obvious applications in antennas but is also useful in power supplies and can even be used to stop high-current spikes.
Electrons have mass. Is the weight of a large electric cord or coil with electricity running through it higher than a one without electricity? Can we see the difference in weight when power is switched on or off? Thanks
You aren't really adding or subtracting electrons with the vast majority of electric flow, you're moving them. There are, of course, times when they are added or subtracted (static electricity) but then the actual number of electrons moving is so small that I imagine it's immeasurable. But in THOSE cases, there would be a very, very miniscule difference, I believe.
ALL electrical conductors have inductance. You don't have to coil anything. This is simply because electrical current flowing through a conductor results in a magnetic field around the conductor and energy is stored in the magnetic field. Current flow through a conductor causes a magnetic field to be produced around the conductor. If the current is changing the strength of the magnetic field also changes. The changing magnetic field induces a voltage in the conductor through which the current is flowing. That voltage opposes the voltage which is causing the current flow. I have NEVER seen a single word about the mass of an electron with regard to inductance. I'd have to play this video again to be sure, but I didn't hear the word "magnetic" once! You cannot discuss inductors without the concept of energy stored as a magnetic field. You *cannot* ignore inductance in DC circuits. Inductance must be considered in any circuit in which current flow is not perfectly constant. In fact the most important property of a inductor is that it impossible to instantaneously change the current trough it. All of the basic switchmode power converters are dependent on inductors in which the direction of current flow is always unidirectional. The _magnitude_ of current changes but the direction of flow does not - it is DC.