When you start learning a new concept in any subject (not just in electronics), it is always important to grasp the basics before moving on to deeper details. Since this page is all about technology, here is a brief explanation of some basic electronic components which is a to know before attempting any project.
A resistor is a device that reduces current in a circuit by offering obstruction to the flow of electrical current. So if you connect an LED directly to a 3v battery and then connect it by adding a resistor in series. The brightness in the second case would be lower than the first one as the resistor in the second case would not allow much current to pass through thus reducing the brightness. Resistance is measured in ohms, kilo ohms and mega ohms.
A capacitor is a device that stores electricity inside it when it is supplied and gives it out in a circuit when there is a loss in electricity. It is like a rechargeable battery but there is a lot of difference between them. A capacitor can store a small amount of current and can charge instantly whereas a battery can store a large amount of current and takes a while to charge. There are many types of capacitors but the two common types are- electrolytic (polarized) and non electrolytic (non polarized). Capacitance is measured in pico farads, nano farads and micro farads.
A transistor is a device that amplifies a small current applied on its base pin to produce a large current that flows between the collector and emitter pins. It does not create a large current but acts as a switch which when supplied a small current on the base pin, closes the switch (switches it on). There are two types of transistors- NPN and PNP.
(4) Integrated Circuit (IC):
An integrated circuit is a small package that is made for a particular task. It has a miniature inbuilt circuit that has many components inside it can perform a particular task. For example- a 555 ic is meant for timing circuits and LM386 is meant for amplifying audio signals. It is usually a small black chip with pins coming out. There are 3 pin ics as well as 32 pin ics and even more.
A diode is a device that allows current to flow only in one direction. This is the reason it has polarity and should be connected correctly for its proper functioning. It is used to prevent the reverse flow of current.
(6) Light Emitting Diode (LED):
A light emitting diode is a special type of diode that can emit light when electricity is passed through it. Like a diode, an led also allows current to flow only in one direction so to make it work it should be connected properly in a circuit. These days LEDs are preferred over lightbulbs as they consume much less electricity than bulbs and CFLs. They are available in different shapes, sizes and colors but being energy efficient, their cost is much high.
A potentiometer or a variable resistor is a device that allows us to choose different resistances that may be required in a circuit. It has a knob that can be adjusted to produce a specific resistance.
(8) Light Dependent Resistor (LDR):
An LDR is a special type of resistor that changes its resistance according to the intensity of light falling on it. The resistance of an ldr increases when it is dark and decreases when the intensity of light falling on it is high.
(9) Infra-Red Receiver (IR receiver):
An IR receiver is a device that receives infrared light and gives an output depending on the signal received. It decodes and tells the type of signal received. It is present in all the devices that are controlled using IR remotes.
(10) Seven Segment Display:
A seven segment display is a device that is used to display digits and letters. It has usually a series of seven leds put in a certain odder to form an 8. All the digits can be displayed by lighting a certain number of leds. It also has an extra led for decimal point.
That's the end! Hope this was helpful..