what is electronic electronic is The study and use of electrical devices that operate by controlling the flow of electrons or other electrically charged particles.
We use many component to control electricity these are the some of component
RESISTER
CAPACITOR
INDUCTOR
TRANSISTOR
RESISTORS - Resister is two terminal passive component that use to reduce current flow.
CAPASITOR - This is passive device which can store electric energy.
INDUCTOR - It is passive electronic device that store electric energy in magnatic field when electric current flow through it
TRANSISTOR - Transistor is a semiconductor device that use as a switch or amplifier .
Example of these components
RESISTORS
Resisters use to reduce electric current flow so if we want reduce voltage to low voltage we use resister. Resisters value measure in Ohm their are different type of resisters basically their are two type
Liner resisters
Non liner resisters
lets see what are these resister types and how they build.
01.Carbon composition resister.
A typical fixed resistor is made from the mixture of granulated or powdered carbon or graphite, insulation filler, or a resin binder. There are two conductor wires on the both ends of the resistor for easy connectivity in the circuit via soldering. A plastic coat covers the rods with different color codes (printed) which denote the resistance value. They are available in 1 ohm to 25 mega ohms and in power rating from ¼ watt to up to 5 Watts. they are less stable means their temperature coefficient is very high. Also, they make a slight noise as compared to other types of resistors.
Wire wound resistor is made from the insulating core or rod by wrapping around a resistive wire. The resistance wire is generally Tungsten, manganin, Nichrome or nickel. The manganin wire wound resistors are very costly and used with the sensitive test equipment. They are available in the range of 2 watts up to 100 watt power rating or more. Wire wound resistors make lower noise than carbon composition resistors.
All thin film resistors are made of from high grid ceramic rod and a resistive material. A very thin conducting material layer overlaid on insulating rod, plate or tube which is made from high quality ceramic material or glass. There are two further types of thin film resistors.
those resistors which values can be changed through a dial, knob, and screw or manually by a proper method. these types of resistors, there is a sliding arm, which is connected to the shaft and the value of resistance can be changed by rotating the arm.
Potentiometer is a three terminal device which is used for controlling the level of voltage in the circuit. The resistance between two external terminals is constant while the third terminal is connected with moving contact (Wiper) which is variable.
Rheostats are a two or three terminal device which is used for the current limiting purpose by hand or manual operation.
There is an additional screw with Potentiometer or variable resistors for better efficiency and operation and they are known as Trimmers.
Non Linear Resistors
Thermistors is a two terminal device which is very sensitive to temperature. In other words, Thermistors is a type of variable resistor which notices the change in temperature. Thermistors has a negative temperature coefficient (NTC) but there is also a PTC (Positive Temperature Coefficient) which a made from pid Barium Titanate semiconductor materials and their resistance increases when increases in temperature.
Varisters are voltage dependent Resistors (VDR) which is used to eliminate the high voltage transients. In other words, a special type of variable resistors used to protect circuits from destructive voltage spikes is called varisters.
When light falls on the photoconductive cells (LDR or Photo resistor), then there is an increase in the free carriers (electron hole pairs) due to light energy, which reduce the resistance of semiconductor material (i.e. the quantity of light energy is inversely proportional to the semiconductor material). It means photo resistors have a negative temperature coefficient.
Resistors are used:
•For Current control and limiting
•To change electrical energy in the form of heat energy
•As a shunt in Ampere meters
•As a multiplier in a Voltmeter
•To control temperature
•To control voltage or Drop
•For Current control and limiting
