Components - Resistor

Okay,here we go.Today i'm going to write about the most simple component out there.It's called a resistor.It's main feature is that it creates ohmic resistance,and it's mainly used for protection of some other components.Resistance can be used to calculate current if the voltage is known.This is done by Ohms rule.

Georg Simon Ohm(16th march 1787-7th july 1854)

First the main factors in this:

I=current,measured in ampers(aka amps)[A]

V=voltage,measured in volts(duh)[V]

R=resistance,measured in ohms[Ω]

And the rule: I=V/R

So,if you connect a 1Ω resistor to 1V the current of 1A will flow.Considering that the current of less than 50mA is required to kill a human 1A is very strong current.Of course a 1V battery won't kill you because of the resistance of your body which is way greater than 1Ω.

This is a resistor.See the colored bands?They are very important.By knowing what they mean you can know everything about that resistor.

Here's the explanation:

Okay,now i'm going to calculate the resistance of that resistor on the picture.The colors are:

orange-orange-white-black-brown

Since orange stands for 3 and the first two stripes are orange the number were looking for is 33#x#.Now the third stripe is white.White stands for 9.The number is 339x#.The fourth one is multiplier.Since it's black the multiplier is 1(339x1).Fifth stripe is brown,thats the tolerance.Brown means its 1%.Now the resistance is calculated.It's 339 ohms with 1% tolerance.I hope you understood that.

This is how the resistors are drawn in the circuit schematics.Remember the upper one because it's used in "Electronics Workbench",the software used to simulate circuits.It's very useful for beginners.I will explain more later in one of my following posts.

Now resistor connecting.You can connect them in a series or a parallel.

When they're in a series the equivalent resistance(Re) is calculated by simply adding the resistances of the resistors in a series.

Example:

Since there are five resistors we calculate the Re as following:

Re=R1+R2+R3+R4+R5.

Re=22+50+17+170+70

Re=329 ohms

See?It's that simple.

Now parallel connection.It's when you connect one side of each resistor in one point and the other side in the other point,as shown on the picture.

Now here's how you calculate this.

1/Re=1/R1+1/R2+1/R3

1/Re=1/20+1/10+1/5

1/Re=1/20+2/20+4/20

1/Re=7/20

7Re=20

Re=20/7

Re=2,86 ohms

Not as simple as the serial connecting but it's also pretty simple.

And that's the end of this.If you want to practice the thing you learned today here are some tasks.

1.Calculate the resistors

a.)red-blue-yellow-orange-blue

b.)brown-green-black-orange-green

2.Calculate the equivalent resistance:

Tip:First do the parallel connection(mark it Re1) then you will have three resistors in a series.Calculate that and you will get the equivalent resistance for that entire mixed connection.

And remember,electronics is the future.Learn some today.

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