Thursday, September 23, 2010

Voltage Resistance and Current

I'm going to take this post to explain just what voltage is and how it relates to circuits.

Voltage is defined as a the measure of the push on each electron as it moves through the wire.

A nice analogy I heard to think of voltage is to think of water going down a hose, the pressure of the water in the hose can be thought of as voltage, the more pressure you apply the faster it goes through the hose and the more voltage you have the faster the electrons move through the wire. Voltage is measured in Volts abbreviated V or E depending on what circuit you are working with.

Resistance can be thought of as how easily the water is able to flow through the hose. The bigger the hose the easier it is for the water to flow through. Likewise, the less the resistance in a circuit the easier it is for electrons to pass through. Inveresly if you make the hose smaller in diameter you decrease the speed at which water can pass through the hose at a given pressure. Think of that as increasing resistance in a circuit, the more resistance the less the electrons are able to flow through the circuit.

Resistance is a nice intuitive word since it just means to resist the flow of current and its right there in the name. Resistance is measured in Ohms which is symbolized either with R or the greek capital letter Omega.

Current in a circuit can be thought of as the amount of water flowing past a certain point every second. It takes around 6.241 × 1018 electrons passing a given point each second constitutes one ampere. You don't really need to know that it is that many electrons just remember that an Amp is a measure of the amount of electrons passing through in a given amount of time. Current is measured in Amps abbreviated either A or I.

Here's a sample circuit that shows where they fit in to a layout and how they are calculated.


  1. Hey! Being a computer science student and having absolutely no idea of anything relating to electronic engineering/technician this has been really helpful. I've always been interested in the subject and find I might pursue it as a minor during my studies.

    Keep up the good work!

  2. Nice article man, cant wait for your next one

  3. If I keep following this maybe I'll learn something about making a rat into a real-life Megavolt. 8|

  4. followin 'n' supportin 'n' fappin bro :)

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  5. It's weird reading about 8th grade (?)physics I never bothered to remember in english.
    Feels familiar but then again the english names are off-putting enough to feel uncomfortable with it. :D
    I'll keep reading.

  6. This was interesting.. I guess I should be a tad ashamed to admit I didn't really know this before. You learn something every day I guess

  7. cool, i always wondered about stuff like that

  8. I can never grasp this no matter how i try., water analogies kill me