Minute 9:12, does the position of the Resistor matter? I mean given the flow direction, should the resistor be between the input and the LED lamp, so it will slow doen the current before it reaches to the lamp, or does it not matter? When not, how and why? Maybe someone wll explain, thank you!
There are those who use magnets and coils to light light bulbs. I can’t find out what the magnetic flow or current flow is as the lights don’t glow for me. Please tell what size light bulbs are used for this purpose. I have illuminated a bulb with a 9v battery, however I cannot achieve 100% free power to make light. Thanks
At 4:05 you say: "We can convert AC to DC using an inverter" and then show a drawing on how DC is converted to AC. Either this is a small oversight or I am missing something?
Man did I luck out. I was on a little wikipedia-train going through articles on electricity, as my understanding isn't super great (physics was my worst class in high school). I came to youtube to look for 'how does a transformer work', found your video, and come to find this series of videos that is actively being uploaded (this specific video is a day old). Crazy luck. Also, 'All the power!'.
Great videos paul. Im a master electrician in the usa. Iwas trying to explain transformers to my apprentice and realized i had a lot of questions. This is your fourth video ive watched, you do a great job of using language and analogies that anybody can understand. Keep up the great work mate
@@MichaelJ44 Current always rises when the resistance drops which is why short circuit is so dangerous since there is no resistance. The higher the resistence the lower the current and the higher the voltage the higher the current's potential. It is a side effect basically of resistance and voltage.
4:02 There's an error: in the video, you've said that you convert AC to DC using an inverter. That is wrong. You convert DC to AC using an inverter. AC to DC is converted using a rectifier.
mjchmara1 it looks like a typo. It should read: One Amp = One Coulomb per Second and 1 Coulomb = approx 6,000,000,000,000,000,000 electrons. Well spotted...
Great video, but a few inaccuracies: E.g. "One Ampere is equal to one Coulomb" is an unfortunate way to put it - as Coulomb is charge, not current. It is claimed (in the same slide) that one Coulomb is equal to a certain number of electrons per second. No, that is current, not charge. This ought to be corrected, as is very basic and confusing for people who are learning electronics. An inverter converts DC to AC (4.04): The graphics is correct, but the commentary describes it as a rectifier, not an inverter.
3 ampéres = 1,8726x10^19 electróes/segundo e não 1,93x10^19.OK?! Espero que me diga se estou certo ou estou errado. Muito obrigado. Abraço de Portugal.
Case1: If we place 2 resistor in parallel of same value.(1k0hm) Case2: If we place place 3 resistor of same value.(1kohm). Which case draws more current from battery.
Great video, except for the ending. A circuit breaker exists to prevent fires, not to save your life from electrocution. I don’t want anyone to think that you can’t be hurt because a circuit breaker will save them.
I was arguing with my teacher about this. And he said that, technically it is true that the interrupter breaks the circuit due to an increase in current. It's just due to a ground fault instead of an overcurrent. But I would say that such a detail should be mentioned when talking to the audience of these kinds of videos.
@@jasisonee that part was unclear to me. Why touching the live wire will increase the current? Shouldn't the body add an extra resistance lowering the current?
Dear Sir... very good videos. Thumbs up. A bit correction at minute 5:03. 1 Amp is not equal to 1 Coulomb. It is equal to 1 Coulomb per second. I = Q/t
This is a really good video series. I have a degree in Electrical Engineering and found practical things in them I did not know or fully understand. I hate to nitpick, but there is one concept with which I must take exception. That is the depiction of current as physical electrons racing through the conductor at tremendous speeds. It is the electromagnetic wave propagation that moves at incredibly high speeds of approximately 0.9c. In fact, the electrons merely "drift" at about 1mm/sec. I have not watched all of your videos, so I apologize if you have made this distinction elsewhere. Otherwise, keep up the good work.
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Can someone please explain why the current would increase if someone touched an open circuit? Doesn't this go against Ohms law? A human body surely represents a very high resistance, which should cause the current to decrease for a fixed voltage.
*summary:* - electrical current is just electrons moving along a wire - voltage drives an electrical current - DC is when electrons flow in the same direction - AC is when they alternate their direction - you can use an inverter to convert AC to DC - make a resistor the weak point in your circuit to prevent other parts from burning out (these are called fuses)
Incorrect. A resistor and a fuse are very different. A resistor brings current and voltage to a specific point while a fuse is a safeguard that blows when the limit is reached.
@@Rexaurus Are you sure about this? Couldn't I just use an LED (which is a resistor - heats up in response to electron flow and as a result emits light) as a fuse? If I push too much current through my circuit, the LED will burn out, thus protecting the rest of my circuit. I don't really see what makes a fuse a fuse? Aren't they simply resistors internally?
4:02: "We can convert AC to DC using an inverter." Should be the other way round (as one can see on the screen): "We can convert DC to AC using an inverter."
You hurt me. I red your reply and exclaimed out loud... in pain! That is no joke. I really did. What is "education" doing to us? Relieving us of thousands of pounds/dollars, and still requiring us to go on to RU-vid to actually learn stuff? What do we pay for, exactly? (I know "red" is not spelled correctly. That is to avoid "reed".) I feel your pain, man. So sorry.
Hi, he will have used Ohm's law. If you are not familiar with that law, it basically states the relationship between the current flowing between to points and the voltage across them. In short, the voltage across two points 'V' is equal to the product of the current 'I' and the resistance 'R' - so V = IR in short. It's worth memorising this if you can as you will use it all the time. In his example, the LED is rated at 25mA and has a forward voltage of 3.3v. If you are unfamiliar with that, just consider it the amount of voltage "used" by the LED to be in the "on" state. This leaves us with 5.7V of extra voltage to drop, as the battery is a 9V cell. So to compute how much resistance is required to limit the current to 25mA, we can just re-arrange the law in the form R = V/I, where V is our voltage (5.7V) and I is our current (25mA, so 0.025A). If you calculate this value you will get a resistance of 228 ohms, as the minimum resistance required. If you are wondering why the video man selected 270ohms, it is likely because it's the closest standard resistor size to 228 without going to anything smaller. You normally want to play it safe like this because resistors are only guarenteed to be within a certain tolerance of their stated value. I hope that helps.
A typical LED is lighting normally at 20mA for for a 5V supply, the limiting resistor is found by dividing 5000 mV by 20 mA giving 250 ohms. So a 270 ohm resistor will do just fine. Using a lower resistance the LED might be too bright and even burn out, a higher resistor gives a dimmer light.
How is the voltage and current passing through the LED light then into a resistor and not burning up the LED. You would think the resistor would need to be before he LED to slow down the current? Is this a mistake in the video?
Thanks a lot for this video!!! People have been wanting to figure out how to get more voltage out of a solar cell or battery. Well that can't actually be done, but we can make them appear like they are providing more voltage using a current amplifier added. It is similar to how capacitors appear to pass AC electricity, but actually they don't. I drew two schematic diagrams and will get back to you on this idea of mine after testing it. If successful, a 6 volt battery will do what a 12 volt battery can do! 💯💰🙏
My experiment was a success saving as much as 61.9% current when applying 7.53 volts (from a variable DC Power Supply) to a 12 volt DC automotive bulb. Capacitance maximum value changes each time the input voltage changes and also maybe the total impedance of the load device connected to the input source.
1 ampere means 1 coulomb per second? Right? Or 1 amp means only 1 coulomb? Coulomb is not synonymous of ampere? Coulomb per second is ampere. Right? Sorry if this is a bad question.
It is a mistake in the video. 1A=1C/1s or in differential form: I=dq/dt q-electric charge (measured in Coulombs) t-time (seconds) Many also use As (Amp*second) instead of Coulomb.
I don't like that last bit....circuit breakers are NOT designed to be live-saving devices, not at all. If they were, we wouldn't need GFCI outlets in our bathrooms. It only takes a fraction of an amp to kill you, and you're trusting a 15-20A breaker to trip in time to save your life? That's assuming that, for whatever reason, that much current flows into you to begin with. Even if it did, such a massive amount of current would probably kill you instantaneously, and make it a moot point. Not to mention that there are different types of breakers, those that trip instantly, and those that trip after 1-2 seconds of overload (to stop them from tripping if there are tiny transient moments of high current draw). DO NOT trust a circuit breaker to save your life, they are only there to protect the circuitry and the structure, NOT humans!
A small correction. Current is not the flow of electrons. Electrons move very slowly. Current is the flow of charge. And charge somehow travels at the speed of light. This is why electricity confuses me. I cannot understand how electric signal can travel at speed of light while electrons travel at a few millimeters per second.
This is the case when you consider Power (P) to be constant. Because P = V * I, if you increase voltage V, current I needs to decrease (for the same amount of power. For example, a 60W lamp designed to work with 240V will require half of the current than a 60W lamp designed to work with 120V. But, keep in mind that for THE SAME lamp, if you increase the applied voltage, its current will also increase (you will get more power).
Mohd Azmeer Well, that’s not strictly correct. From ohm’s law, increasing the voltage will increase the current and decreasing it will reduce the current and that’s the way to think about it. If it is a 120v circuit with a 60w lamp, increasing or decreasing the voltage will increase and decrease the current, just the same as the 240v circuit. However, for the same power, if the voltage is reduced then the current has to increase I = P/V A transformer is a good example of reducing or increasing the voltage. Say the voltage In is 240v in and 120v out. If the power in, equals the power out then P = Vin x In = Vout x Iout 60 = 240 x 0.25 = 120 x 0.5 So reducing the voltage, increases the current for the same power and increasing the voltage decreases the current for the same power. However, do not confuse this with ohm’s law. These are two completely separated circuits and ohm’s law will apply to both. Increase the voltage of Vin and In will increase. Increase the voltage of Vout and Iout will increase. Assume the transformer has a power factor of 1 and assume there are no losses.
Do electrons actually flow because what I’ve read is that they vibrate and transfer energy. So current should be the rate of flow of energy not electrons.
Yes if you could magnify atoms, you won't see any electrons move like that, just the electron cloud or soup between metal atoms and a very faint wave-like "movement" over it, that is the current. At least that is current in metals. What they displayed is more like movement of free electrons in vacuum. But the presentation is great anyway for engineering classes, here we don't need to go quantum :)
How to find Voltage, Current or Resistance? *FORMULAS* *Voltage* = Current x Resistance *Current* = Voltage / Resistance (divide) *Resistance* = Voltage / Current (divide)
8:47 slows down the electrons? nothing slows down electrons. it can slow down the current(the amount of electrons per time unit through that conductor).
Thanks for this video. I'm still just struggling to understand something..I thought that the current that a battery supplies isnt definitive...that it's all proportionally based on all of the loads used, and the voltage. So Less resistance = more current drawn. Does this mean that current is just ALWAYS 0, initially ? and until we have a voltage(E) and a load(R), we can always calculate it with I = E/R? I feel like something is wrong here.. Cause if we put two batteries in parallel, the voltage stays the same but the current "increases" .. how could something that's based on E/R be increased, if E and R are still the same? how could lightning strike at 200mA+ if I can get shocked at the same voltage but a different amperage, like from a plasma ball? My body's resistance(R) and voltage(E) remains the same in both scenarios. So it's as if the current can be "set" to something regardless of loads in a circuit? I think it's just Ohm's Law that I can't seem to wrap my head around.. :( Any help would be appreciated
@GH1618 have you ever been 11? These kids are barely learning fractions, maybe they could understand very basic principles of electricity, but this video is definitely beyond anyone in elementary school
Great work guys. I am studying for my physics test in electrodynamics and you guys managed to explain to me in 11 minutes what my teacher wasn't able to do in a week. Greeting from Croatia !
I've watched your videos on testing AA batteries - great stuff. You suggest using a 100 ohm resistor with a multimeter; but I find there are 1/4w and 1/2w resistors. Does it make any difference which resistor I use?
I don't understand the example at 10:50 How can a 1.5 V battery rise a current in the circuit if the extra load is added. Wouldn't it be the opposite-the more load, the less current in the circuit?
Sir what actually the electric current is and the mechanism of flow of it in a conductor. I mean is it flows as electrons or as magnetic waves? Do electrons actually move or just they vibrate in the frequency of magnetic waves? I am confused about that so, i hope u clear my doubt. Thank you sir
Thank you for all your videos. I am an old Spanish student who was struggling to understand electricity in my engineering course and I can assure you that I understand a lot more with your English videos than with my Spanish lessons at school. Thanks a lot!..oh and...All the power!
Dude I've had only a vague understanding of what electrical current is for years... Just hearing an explanation that describes amps by the number of electrons per second makes *everything* make so much sense now.
Is the flow of electrons and flow of charges the same definition of current? Nobody has been able to really answer this and cement the idea for. I think it’s important to know because flowing electrons is a big difference than flowing charges. Flowing electrons implies that the electrons are moving, and flowing charges implies that only the charges move.
I like to think of the definition of current as “A *measure* of the flow of charge”, which implies a direction. One Amp equals one Coulomb per second. One Coulomb is the charge on 6.24E18 protons. The charge on 6.24E18 electrons is *negative* one coulomb. 6.24E18 electrons flowing past a point is negative one coulomb per second which is negative one amp. If one insists on defining the reference direction as the direction of electron movement, all currents must be reported as a negative value. I don't have the discipline to do that and to do otherwise is intellectually dishonest. Why not define the reference direction to be “positive voltage to negative voltage”. It’s a convention that makes sense.
Can someone explain to me the situation around 8:05? How can the total amps flowing in the circuit be more than the volts provided by the single power source? (3A flowing in a circuit with a 1.5V battery)
Just look again at time 8:05 only 2 Amps are flowing and that is correct. We have a 1,5 Volt power source and we also must assume that the power source is ideal is has No internal resistance , does not run out of power and the voltage Always is 1,5 Volt. Connected to the power source are 2 lamps, both get the same ( 1,5 Volt voltage ). It all is ohm's law , V = I x R . Amps = Voltage/resistance . The Voltage of the power source does not matter. Let say the power source is only 1 Volt and we connect 10, 1 ohm lamps to the power source. Each lamp gets 1 Amp , so the 1 Volt power source then supplies 10 Amp.
That LED lamp still would burn out, but more slowly. When you calculate the amount of the amount of amps across the 270 OHM resistor, it would be 33.33 mA of current. 9V/270ohms = 0.03333. That LED is rated for 25mA
in 9:00 min you give an example for resistor using. ohm law says that to have 25 mA you need a R of 360 ohm. in your example the resistor is 270 ohm/ can you explain? thank you !
If a device can handle 1A so 1C of electrons per second then 1A is that device's tolerable "pressure". So what's voltage then? Because it's not "pressure"... it's the 1A
Yes, exactly. First you calculate each branch (even if you have 3, 4 or more) using the Ohm's law and then add together, to get all current flowing in the circuit.
At 7 min 30 sec, i'm scratching my head to get around this concept of how come the current in a parallel circuit will increase? I can't seems to visualise how come a parallel circuit will increase current... I'm so sorry, kindly advise~ Thank you!
Great explanation, but a circuit breaker wont stop someone being electrocuted, not enough current will flow to trip the device. That's why we use RCD's .
when explaining OHMS, the diagram at 8:00, would the meter calculate 1.5 for the branch after lamp A, because electrons already are being split going towards lamp A, while making its why towards lamp B?
5:04 So much wrong information for such a diligent effort. "One Amp = One Coulomb" WRONG, 1A = 1C / s. "One coulomb = six quintillion [etc] electrons per second." WRONG in multiple ways. (a) Coulomb is a unit of charge, not a unit of something per second. (b) Coulomb is a unit of charge, not a number of electrons. Charge is not "made" of electrons. Rather, electrons happen to carry charge. As do protons, although of opposite quantity. (c) If we use the symbol 'e' to represent the charge which an electron carries, then 1 C = e x -6.242 x 10^18 NOTE THE NEGATIVE SIGN. This is latter point is extremely important, because when discussing current in mundane circuits involving wires, 'current' refers to the rate of flow of charge (not of electrons). Since in wires (but not all media) the actual moving items are electrons and carry a negative charge, their flow constitutes a negative current. This explains why electrons flow through the wire from the negative battery terminal (negative because excess negative charge) to the positive terminal, yet we describe this as a (positive) current (in the direction) from positive terminal to negative. This very small surprise, so frequently badly explained, leads to misunderstandings such as there being an alternative "conventional" current that is mysteriously different than the "real" flow, when in fact it's all part of the same idea that stems from defining the polarity of charge (and the Coulomb) such that protons have a positive quantity of charge, and electrons negative. Oh, and the slide also appears to say that six quintillion [etc] = 6.242x10 to the negative 18th power, when actually it's the positive 18th power. On close inspection, that is perhaps a caret character, which is meaningless and confusing when you write the exponent as a superscript.
