A person who is beginning to understand electrical circuits and electronic devices has to deal with many elements that are literally stuffed with a circuit board. One of the most common parts used in electronics is the resistor. It is designed to perform several important functions and often cannot be replaced by other elements of the circuit.
What is a resistor
The term "resistor" comes from the English verb resist, which means "to resist", "to obstruct", "to resist". Literally translated into Russian, the name of this device means "resistance". The fact is that a current flows in electrical circuits, which is experiencing internal opposition. Its value is determined by the properties of the conductor and many other external factors.
This current characteristic is measured in ohms and is related to current and voltage. The resistance of a conductor is 1 ohm if a current of 1 ampere flows through it, and a voltage of 1 volt is applied to the ends of the conductor. Thus, with the help of an artificially created resistance introduced into the electrical circuit, it is possible to regulate other important parameters of the system, which can be calculated in advance.
The scope of application of resistors is unusually wide; they are considered one of the most common installation elements. The main function of the resistor is to limit and control current. It is also often used in voltage dividing circuits when it is necessary to reduce this characteristic of the circuit. Being passive elements of electrical circuits, resistors are characterized not only by the value of the nominal resistance, but also by the power, which indicates how much energy the resistor is able to dissipate without overheating.
What are resistors
Electronic appliances and household electrical circuits use a variety of resistors of various shapes and sizes. These miniature devices differ from each other not only in appearance, but also in face value and performance. All resistors are conventionally divided into three large groups: constant, variable and trimmer.
Most often, in devices you can find constant-type resistors, resembling oblong "barrels" with leads at the ends. The resistance parameters in devices of this type do not change significantly due to external influences. Small deviations from the rating can be caused by internal noise, temperature changes or the influence of voltage surges.
For variable resistors, the user can arbitrarily change the resistance value. For this, the device is equipped with a special handle, which has the form of a slider or can rotate. The most common member of this family of resistors can be found in volume controls on audio equipment. Turning the knob is able to smoothly change the parameters of the chain and, accordingly, increase or decrease the volume. But the trimmer resistors are intended only for relatively rare adjustments, so they have not a handle, but a slotted screw.
