The Basics II

Now that we’re done with the basic terminologies, and basically, the “soft” part of electronics, we go to the “hard” part (hard doesn’t necessarily mean difficult… it means something tangible like resistors etc). Make sure you’re in a comfortable seat `coz this will be a long one.

We’ll start with the humble resistor.

3D Visualization

Diagrammatic Symbol

A resistor contains resistance and therefore, is used to limit the current in devices, IC’s, wires, and components.

Usually, a resistor contains 4 color bands and is read from the opposite side of the gold or silver band (for a beginner, it is less likely that you will use resistors other than the common one as shown in the picture).

The first two bands indicate the first two significant digits, the third band indicates how many zeros are there and the fourth band indicates the tolerance level (yep, a 470 ohm resistor doesn’t mean you get an exact 470 ohms, as it could be 472, 468 etc. depending on the tolerance level)

Now you might be asking, what the heck does red stand for? Patience... lol

Here is a table of what each color stands for:

Color	Digit (1st and 2nd Band)	Multiplier (3rd band)	Tolerance
Black	0	1
Brown	1	10
Red	2	100
Orange	3	1000
Yellow	4	10000
Green	5	100000
Blue	6	1000000
Violet	7	10000000
Gray	8	100000000
White	9	1000000000
Gold			5%
Silver			10%

That means the resistor in the picture above has a value of 220 ohms with 10% tolerance.

Everything’s messed up? Don’t worry as you’ll get a better understanding of resistors once we get to the actual circuit-building stuff.

Next in line is the Diode.

3D Visualization

Diagrammatic Symbol

A diode permits current to flow in only one direction. Actually, if I would explain the whole operation of the diode, you would be probably looking for funny videos at YouTube now because of boredom, so let’s just stick with that “nutshell” definition. Oh, and I think I should mention this now, the current flows towards the direction the arrow is pointing in the diagrammatic symbol and towards the white line in the real thing. Like what I’ve said with the resistors, you’ll have a better understanding of the diode once we get to the actual circuit-building stuff.

Since we already talked about the diode, let’s move on to it bigger brother, the transistor.

3D Visualization

Diagrammatic Symbol

A transistor is basically a pair of diodes which function like a switch. It has three pins, the collector, base, and emitter.

Like the diode, a little complex science is behind the operation of the transistor and involves terms like holes, electrons, doping, depletion region, etc. and I don’t want to make a long explanation regarding those stuff. For now, let’s just say that the transistor functions like a faucet where the collector is the supply tank, the base is the knob, and the outlet is the emitter. When you apply no force to the knob (base) and it remains unturned, no water flows from the supply tank (collector) to the outlet (emitter), but as you turn the knob, water starts to flow relative to how much you turn it.

The transistor allows current to flow from the collector to the emitter when current is supplied to the base, and how much current flows from collector to emitter depends on how much current the base receives.

Lastly, we go to the Capacitor.

3D Visualization

Diagrammatic Symbol

Yep those mini barrels are called capacitors, and we all know barrels store a lot of things.

Capacitors have the ability to store electrical charges and discharge them later on.

In a diagrammatic perspective, there are two types of capacitors, the polarized (electrolytic) and the non-polarized. Basically, electrolytic capacitors have a negative and a positive pin and this should be forgotten on circuit assembly. Trust me when I tell you, when you place electrolytic capacitors in a way that the negative end is connected to the positive supply and the positive end is connected to the negative (or ground) supply, BAD THINGS HAPPEN. Usually, tiny orange glowing stuff go flying up with a bang and when you look at your circuit, you’ll see only the pin of the capacitor is left.

When we start our first project, the universal power supply, you’ll learn more about these four basic components. (Actually, there should be five, the inductor being the last but I figured, this post is too long for that, and I’m feeling lazy right now to add more stuff lol)

The 3D visualizations are from eagle3D and the schematic symbols are from eagle 5.6