Electronic Basics #12: Coils / Inductors (Part 1)

resistors capacitors and inductors Or coils are the most important basic passive components in electronics? You can find coils very often in different situations. That's a coil. That's a coil That's a coil. That [is] a motor which consists of coils that's a Transformer which is also made out of two coils And that's a relay which does also consists of a coil you get what I mean So in this video. Let's talk about the basics of inductors, and why they are so important Let's get started first of all Let's get one foundation straight when current flows through a wire it creates a [magnetic] field around it more current means a bigger fields we can even measure this fields by using my current probe which then Calculates it to a current value, but don't overdo the current flow Otherwise our wire can't handle it and starts glowing This is actually one basic characteristic value of coil the maximum current as an experiment let's see how the voltage of our mains power looks like It's a beautiful sine wave now I use the probe to see whether I'm a voltage source HmM this looks familiar But why? Well the magnetic field of our mains wires which are all around us inside our [walls] Induce a small voltage on to us because we are basically a big antenna speaking of induction we induce a voltage if a conductor moves inside the Magnetic fields like a ac motor right here, or Dc. Motor or when a Magnetic field is changing its intensity like it happens with all Ac signals But the Magnetic [field] of plain wire is quite weak and cannot even lift up this nail That is why we can wind up our wire to create a bigger length which increases our Magnetic force But it is still not strong [enough] so we have to use a ferromagnetic material for example iron as a core to enhance our fields this does the trick and we have successfully created an electromagnet [relays] use such a trick to trigger a switch that can handle high Ac currents Depending on the dimensions windings and ferromagnetic core of your coil. It can create a weak or Strong Fields this property is represented with the value inductance Which is measured in Henry you can measure the inductance with an RLC meter. Which is a bit expensive Or you can calculate it through different measurements, but that is far beyond this basics video now Let's see what a coil. Does in a DC circuit in such a circuit the voltage can only switch on or off [it's] pretty simple. [I] simulated here with a square wave signal Which is connected to an amplifier, and then a coil and led with current limiting resistor? Normally, with a resist- led combination the current would follow our voltage signal without [a] problem But now with the coil current does not follow our voltage Immediately and takes a bit of time to reach its final state With more inductance this can take longer and with less inductance of our coil it can take less time But why the reason is called Lenz law? The voltage at our circuits lets current flow this current starts creating a magnetic field Which induces voltage into the coil itself? which produces an induced current and Lenz law says that such a current will always oppose the change it produces Sounds complicated [but] in a nutshell it says we want current to flow, So our coil will hinder it as good as it can or we want currents to stop flowing, so our coil will use the energy of its magnetic [field] [to] pump current into the circuit again and it hinders again as good as it can. Seems like coils are plain annoying, but we can use them to our advantage the energy stored in an inductor is L divided by 2 Multiply it by I squared and we use this energy For example in Boost converters to get 5 volts out of three point seven volt batteries here is the circuit Firstly we close this switch to create the Magnetic fields around our coil then we open the switch now our coil pumps the energy into our circuit and Rises the output voltage at the end, but we also have to be careful I'm using a Pwm signal to adjust the speed of a motor since the motor Consists mostly of coils we have a problem when our transistor switch closes the coil tries to push the energy inside the open circuit which produces a huge Electron [access] and thus peak voltage spikes which can easily destroy our transistor So we use a flyback diode to protect our switch by offering the current a way to flow Or we use a coil at the output of a step-down converter Or switching power supply so that we have an [energy] storage which keeps our output voltage at a constant level Now you know how inductors behave in DC circuit's check back with part two to find out about frequency filters Reactance and basically how coils behave in Ac circuits until then don't forget to like share and subscribe For more electronics basics stay creative, and I will see you next time

Channel: GreatScott!

Views: 1,211,477

Keywords: Electromagnetic Coil, Electronics (Field Of Study), Inductor, coil, greatscott!, Energy, basics, tutorial, basic, knowledge, inductor, inductance, RLC meter, passive component, induction, lenz law, flyback diode, boost converter, buck converter, magnetic field, MF, electro magnet, electromagnet

Id: kdrP9WbJIb8

Length: 6min 27sec (387 seconds)

Published: Sun May 17 2015

Reddit Comments

[u/GreatScottLab]

Thanks for sharing ;-)

[u/Zequez]

Well, this comes in handy, since it's the last topic we discussed on my physics class haha, thanks.

[u/anymouse_404]

Three months ago,I could have gone crazy, trying to wrap my head around coils at school. Frankly, it was a bit more advanced, the ac, wave shift, complex numbers, crazy stuff.