Components and Diagrams


Schematic Diagrams

In electronics, a schematic diagram shows how components connect with another. It is basically an outline of the circuit. Each type of component has a unique symbol and a name. All relevant values and component specific information are usually included.

Here are a few examples:











Components

I will just be talking about a few of the basic components in electronics, please keep in mind there are many more, here is what I will be explaining:

• Resistors
- A component that resist the flow of electrons.
• Capacitors
- A mini recharable battery.
• Diodes
- A \"one way street\" for electrons.
• Transistors
- A component used for switching and amplifying.
• Integrated circuits
- An overview of integrated circuits
• Switches
- Discusses the different configurations of switches.

Resistors

Resistors are one of the most commonly used components in electronics. Resistors resist the flow of electrons. They are needed to add resistance to circuits.

The colour bands around the resistors are colour codes that tell you its resistance value. As I mentioned in the previous tutorial, resistance is measured in Ohms.
The tolerance bands indicate the accuracy of the values. A 10% tolerance (silver band) for example, indicates that the resistor will be within 10% of its value.





To read the Resistor, you must hold the resistor so that the tolerance band ( Gold or Silver) is facing to the right.
The first two colour bands from the left are the significant figures - simply write down the numbers represented by the colours. The third band is the multiplier - it tells you how many zeros to put after the significant figures. Then put all the figures you have together to get the total resistance.

Here is an example:





A resistor has two different smbols, one for Americans and the other for Europeans, the symbols are as follows:





This is American





This is European.

A resistors schematic name is R

Capacitors

Capacitors can be thought of as rechargeable batteries -- Capacitors can be charged and discharged. The amount of charge that a capacitor can hold is measured in Farads or the letter F. However, 1F is too large for capacitors, so microfarads(µF) and picofarads(pF) are used.
Micro = *10^-3
Pico = *10^-12
So 100,000pF = 0.1µF = 0.0000001F

We will only be discussing two types of the most commonly used capacitors: Ceramic and Electrolytic.
• Ceramic capacitors are brown and they have a disc shape. These capacitors are non-polarized, meaning that you can connect them in any way. To find the value, you simply decode the 3 digit number on the surface of the capacitor. The coding is just like the resistor colour codes except that they used numbers instead of colours. The first 2 digits are the significant figures and the third digit is the multiplier. These capacitors are measured in pF.








Electrolytic Capacitors have a cylinder shape. These capacitors are polarized so you must connect the negative side in the right place. The value of the resistor as well as the negative side is printed on the capacitor. These capacitors are measured in µF.









Diodes

Diodes let electrons flow through them in only one direction and blocks flow of electrons in the opposite direction. Diodes flow from cathode to anode. The cathode side of the diode is marked with a band around it.





There are basically three different types of diodes: Diodes, Zener Diodes, and Light Emitting Diodes.

Zener diodes have a set voltage rating. When a voltage exceeds the voltage rating going the opposite direction (from anode to cathode), the diode allows the electrons flow.





Light Emitting Diodes (LED) are like the regular diodes except that it lights up when electrons are flowing through. There aren't any numbers or letter on an LED, but one pin is shorter than the other, the longer pin is the anode, positive.





Transistors

Transistors are used as switches and amplifiers. I will discuss two types of transistors: PNP and NPN transistors. Both of these transistors have 3 pins: emitter, base, collector.

To allow electrons to flow through the collector and emitter of a PNP transistor, the following must apply:
The emitter is more positive than the base and the collector leads to the negative.





The NPN transistor is the opposite:
The collector must be more positive than the base and the emitter leads to the
negative.




This is what transistors look like,





Integrated Circuits

Integrated circuits (IC) are usually referred to as chips. Inside them is a tiny piece of semiconductor(usually silicon) with large circuits built in.


This is what they would normally look like:




The general types of IC'S normally include:

• Logic circuits -
These IC\'s are basically decision makers. most contain logic gate circuits. (logic gates will be discussed in a later section).
• Comparators -
These IC\'s compare inputs and gives an output.
• Operational Amplifiers -
These are amplifiers. Works very much like transistor amplifier circuits.
• Audio amplifiers -
These are used to amplify audio.
• Timers -
These are counting IC\'s used for circuits that counts or needs to keep track of time.
• Switches -
Switching IC\'s are also very much like the switching circuits of transistors.
• Other -
There are thousands of other types. A lot of IC\'s are made for a special purpose like digital sound recording. Most IC\'s come with pinout information and how to use it. If not, you\'ll need one of those large reference books that have info on most of the IC\'s.

Switches
Switches really don\'t need any introduction. It simply connects and disconnect a circuit. This section gives an overview of the contact configurations.

There are 3 commonly used configurations: SPST, SPDT, and DPDT.

SPST = Single Pole, Single Throw
This is a two terminal switch that opens and closes a circuit.



SPDT = Single Pole, Double Throw
This is a three terminal switch that connects one terminal to either of the other two.



DPDT = Double Pole, Double Throw
This is a six terminal switch that connects a pair of terminals to either of the other two pairs.