Resistors are the most basic component in the electronic world since their operation could be described by one of the basic principles of electricity, Ohm’s law. Because of this reason resistance is measured in ohms. When it is required to put some resistance to a branch of the circuit resistors could be used. They are very small devices and polarity doesn’t need to be considered when using resistors because they could operate either way. Since the devices are pretty small a color code is used to exhibit the ratings of the device. Next to resistors most commonly used device in electronic circuits would be the capacitor. A capacitor is capable of temporarily storing an electrical charge. Capacitors come in several varieties, two most common being ceramic disk and electrolytic. Capacitance is usually measured in micro farads abbreviated μF. Here also polarity of terminals is not an issue.
The next most common device would be the diode. Diode is an electronic device which allows current to flow in only one direction. There are two terminals in a diode known as anode and the cathode. Current will flow through the diode only when the voltage applied to the anode is higher than the voltage applied to the cathode. So when using a diode polarity of the terminals must be taken in to account. Usually it is preferred to apply positive voltage to the anode and negative voltage to the cathode. This type of operation is known as forward biased operation.
Light emitting diode is also a very common basic electronic component which has all the characteristics of above mentioned diode and in addition it emits light when subjected to forward bias operation. Simply when current flows through the LED it emits light. As a convention these are produced so that the anode terminal is somewhat longer than the cathode terminal for convenience of identifying the polarity of the device.
The transistor is another basic electronic component which actually is considered to be one of the most important devices in electronics. It has three terminals known as base, collector and emitter. The voltage applied to the base can be used to control the current flow across the other two terminals. Transistor is considered important because it is the device which introduces the concept of voltage gain (current gain in some applications)
Integrated circuits could also be considered as common basic electronic components. An integrated circuit is a special component that contains an entire electronic circuit, complete with transistors, diodes, and other elements, all photographically etched onto a tiny piece of silicon. In most cases they require external power to operate.
All of these devices have their own circuit symbols which are used to represent them in circuit diagrams. If you are looking into studying electronics and building electronic circuits UTSOURCE would be a great choice as your long term component supplier since it is reliable and fast. UTSOURCE is an online electronic device store where you can fulfill all your requirements just at home. It offers various paying solutions such as PayPal, VISA, and Western Union. Check it out at http://www.utsource.net/