Whats is a resistance?
The property of a substance, which oppses the flow of an electric current through it is called a resistance. Its is measured in ohms and is represented by letter ‘R’.
Each resistor has two main characteristics.
1) Its resistance value in ohms and 2) its power dissipating capacity in wattsResistors are employed for many purposes such as electric heaters,telephone equipments, electric and electronic circuit elements and in current limiting devices. As resistors are used in wide applications there values like power rating,R value, tolerance etc vary. Resistors of resistance value ranging from .1ohms to many mega ohms are manufatured. Acceptable tolerance levels range from +/- 20% to as low as +/-.001%. The power rating may be as low as 1/10 watts and can be in several hundred watts. These all vary in range and type of application a particular resistor is used.
Classification of Resistors:From operating conditions point of view, resistors can be classified into two.
1) Fixed resistors
2) Adjustable/ variable resistors
1) Fixed resistors are further classified into:
a) Carbon composition type resistors b) Metalized type resistors c) Wire wound type resistors
a) Carbon composition type resistors:
This is the most common type of low wattage resistor. The resistive material is of carbon-clay composition and the leads are made of tinned copper. These resistors are cheap and reliable and stability is high.
b)Wire wound resistors:
These resistors are a length of wire wound an insulating cylindrical core. Usually wires of material such as constantan (60% copper and 40% nickel) and manganin which have high resistivities and low temperature coefficients are employed. The completed wire wound resistor is coated with an insulating material such as baked enamel.
c) Metalized resistors
It is constructed using film deposition techniques of depositing a thick film of resistive material onto an insulating substrate.Only approximate values of resistance can be had by this method.
2) Variable resistors
For circuits requiring a resistance that can be adjusted while it remains connected in the circuit(for eg: volume control on radio), variable resistors are required. They usually have 3 lead two fixed and one movable.
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ReplyDeleteElectronic components are devices that are part of an Printed Circuit Board Assembly, Since there is great variety are usually encapsulated in different types of materials such as ceramic, metal or plastic.
ReplyDelete10 Electronics Parts used by Electronic Assembly Companies
Resistance
It is an element whose main characteristic is that of the opposition to the passage of the current, its unit of measurement is the ohm (Ω).
Some of its applications are:
Voltage dividers
Protect voltage sensitive devices.
Limit the current of a circuit
Capacitor
The capacitor is a device that stores energy in the form of an electric field, its average unit is the farad, since the farad is a very large unit of measure normally the μf (microfarads) are used.
Some of its applications are:
Filter to eliminate the voltage curl.
Couplers between amplifying stages
Filters pass low
Circuits of radio receiver or oscillator.
Coil
The coil by its shape (coils of wire wound) stores energy in the form of a magnetic field. Every cable through which a current flows has around it a magnetic field generated by the current.
Some of its applications:
Electric motor
Doorbell
Transformer
relay
LED diode
It is a special type of diode, which works like a common diode, but when it is crossed by the electric current it emits light. This process is done thorough LED Assembly There is a great variety of colors. Its applications are mainly based on visual indicators.
Diode
Its operation depends on the polarization that has been applied to it, in reverse polarization the diode works as a switch, in direct polarization it lets the current pass but it consumes a voltage drop 0.7v.
Some of its applications are:
switch
Protection of circuits or electronic devices.
Trimmers
Rectifiers
Construction of voltage multipliers
Switch
Transistor
It is an electronic component formed by semiconductor materials, very commonly used, as we find it present in any of the everyday devices such as radios, alarms, cars, computers, etc.
A transistor is a component that basically has two functions:
- It passes or cuts off electrical signals from a control signal (switch).
- It works as a signal amplifier element.
Relay
It's a magnetically operated switch. This is activated or deactivated when the electromagnet is energized. this operation causes a connection or not, between two or more terminals of the device
Applications
Control of a remote device
It can be activated with a low voltage and drive a high voltage
Insulator switch
Potentiometer
Its operation is like that of a resistance however the value of the resistance is variable and can be varied manually.
Applications
Regulate and / or adjust the voltage in a circuit.
Variable voltage dividers in a circuit.
Fuse
It is used to protect an electrical circuit from an excess current. Its essential component is usually a wire or Metal Core PCB or band that melts at a certain temperature. Its most notable application is to protect an over current.
Transformer
This component is responsible for reducing or amplifying the alternating current, is generally applied in power supplies.
Finally, comment on what component you think has been missing or which should not be.