Electronics Tutorial #4 - Ohm's Law Pt 1 - Relationship between Current, Voltage and Resistance

A tutorial on George Ohm's law for basic electronics and the relationship between current, voltage and resistance.
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Ohm's law states that the electrical current (I) flowing in an circuit is proportional to the voltage (V) and inversely proportional to the resistance (R). Therefore, if the voltage is increased, the current will increase provided the resistance of the circuit does not change. Similarly, increasing the resistance of the circuit will lower the current flow if the voltage is not changed. The formula can be manipulated so that the relationship can easily be seen for all of the three variables.

In this video:

* I use some analogies to explain Ohm's Law and what resistance is and how it affects current and voltage.
* I go through some theoretical examples and then demonstrate these in circuits.
* I show how the theory sometimes does not reflect what happens in practice.
* I introduce some examples I will go through as a practical application of Ohm's law: current shunt, voltage divider, resistor values for LED, Arduino voltmeter.
* I demonstrate my Texas Instruments TI-30XS Multiview Calculator which can make calculating formulas a little easier.
* How to work out resistance in series and parallel?
* How to work out current in a circuit?
* What is voltage / volt drop?
* What is a resistor?

Electronics 101 - Ohm's Law:

Topics for future videos in this series:

* Ohms law, resistance, power, energy
* Electronic components - diodes, transistors, FETS, capacitors, digital logic gates, integrated circuits, 555 timer.
* Series and parallel circuits
* Op amps and feedback

[thaforsaken]

I am 26 years old and knew absolutely nothing about electricity or ohm's law. I've always thought these kinds of things were beyond my intelligence level. You've not only shown me this is within my grasp, but have inspired me to go back to school for it. I have enrolled enrolled in class this Spring.

Sincerely Thank You

[edwardjauregui]

As an electrician who is still learning electrical theory...I can honestly say that your videos thus far are fantastic. I am looking forward to seeing everything you have to share about this subject. I will refer others to you, because these rock! God bless and all the best.

[MikayilAbdullayev]

Man, you teach great. You know, you are one of those rare people who does not skip over anything. Usually, many people skip over small but at the same time very subtle nuances that makes rest of the lesson useless. You definitely don't do so. Instead, you don't get lazy and try to embed what you teach in our minds. Thank you. May God's peace be upon you.

[janetbajan]

I appreciate this so much. I've been studying for my general ham license and accidentally began to study about electronics. I'm 73 yo and female. When I was in school, nothing like this was available to me. I am fascinated by this study and am eating it up. Your videos are allowing me entrance into an area of learning I never had the opportunity to pursue. I thank you so much.

[lavastudios]

this is my favourite youtube series for learning the basics of electronics. i've started watching a few, but this one i've found ideal for keeping it simple, using analogies when relevant without leaning on them too much, and only presenting equations when they are necessary, thereby not scaring off someone like me who never took physics. it's much appreciated!

[hustonfernandes]

I really appreciate the way you teach. I am an Electrical Engineer but what I learned was never able to practically apply my knowledge. This is the first time after years that I can say I now understand what is really going on in my electrical devices.
The best class or series I have ever watched.

[gregoryrichards]

I must say I think your teaching method in style is one of the best I've encountered for a long time. Very thorough, clear and thoughtful directions especially with your diagrams and live examples along with amples of patience. Thank you so much.

[dw]

Last week I decided to finally figure out how to use a multimeter. I watched a couple of videos, learned a little, and promptly forgot it all (just like I did trying to get through college algebra). When I went back, I found yours and have learned - and retained - so much more that I've been watching and really enjoying them all. YouTube can be the perfect learning platform when paired with a naturally gifted teacher, which you certainly are. Thank you. Much, much, much appreciated!

[itdoesntmatter]

I think that my brain just exploded. Like a lot of your viewers/students, we are very interested in learning all about electrical theory and application. I, over my 64 years have always found this sort of thing confusing. Now that I am retired and have the time I am attempting to see the light(pun intended). Thanks for putting this out here. If it hasn't already been mentioned, your teaching technique is very good especially for we folks where things like this don't come easy to understand. Whew! Your patience and graphics are appreciated. Anyway I thank you!!

[aeroplod]

Until today I knew nothing about electronics. I remembered from school (55 years ago) how to rearrange basic equations which helped a little to understand what is an excellent tutorial on ohms law. I understood everything but my 70 year old memory will help me to forget a lot of it!
A truly outstanding video. I might have taken up the subject had my old schoolmasters had this approach instead of mumbling into a blackboard.
Thanks for re-awakening the subject for me.

[mjlorton]

Thanks for your feedback. It best to stick with and use conventional flow from positive to negative. Cheers, Martin.

[toomuchtruth]

Totally agree with this comment.

After many years of having gone/scraped through different physics classes, and watched different tutorials, I'm FINALLY getting an intuitive understanding of these concepts! FANTASTICALLY THOROUGH and understandable teaching.

Thanks so much for these prof. mjlorton !!!

[cliveaitkenhead]

What a great video - Martin puts it across so well and makes it easier to understand than he gives himself credit for. Now for part 2! Many thanks

[mjlorton]

Thanks for the feedback. I think you might want to check the video again. I don't change from 1.5v to 1.05v, the 1.05v is the drop across the resistor.
Cheers, Martin.

[brandons]

I started watching your tutorial series two days ago knowing close to nothing about the subject. I now understand volts, amp, resistance and so much more. Thanks!

[carnot]

I cannot say enough nice things about mjlortons tutorials. Obviously painstaking and compassionate, just what is needed for people (like myself) who have a little trouble catching on. I'm assuming Mr. Lurton is an electrical engineer by training, but he is a born teacher. Bravo Mr. Lorton and keep up your excellent work.

[mjlorton]

Many thanks for the feedback. I'm pleased to hear the videos are of value to you. Cheers, Martin.

[WoundedEgo]

By the way, I think it is awesome that the posters here are, like myself, interested in the subject matter, not in trolling. I delight in a gifted teacher on any subject and in intelligent and polite discourse as well. Kudos to you and the delightful group who have joined you!

[dannuttle]

I like the combination of learning, and simply listening to someone who is personable and patient without ever being patronizing or condescending.

[karakihadi]

I just finished my Civil Engineering degree but I have newly realized interest for electronics. I decided to take learning into my own hands instead of going back to school for it, and I absolutely love your videos. Keep it up!