Technologies, Electronics
What kinds of resistors exist?
When creating technical schemes, details are needed. Resistors are one of the most important. It is difficult to imagine a diagram even for five details, wherever they find their application.
What is a resistor
Classes and tolerance tolerances
- First. Provides for deviations of up to five percent of the nominal value.
- Second. Provides for the presence of deviations, which can reach ten percent of the nominal value.
- The third. This includes devices in which the size of the deviations can reach twenty percent of the nominal value.
And what if such large deviations are unacceptable? There are precision resistors, the kinds of which provide such a maximum difference:
- 0.01%.
- 0.02%.
- 0.05%.
- 0.1%.
- 0.2%.
- 1%.
- 2%.
Other options
Main types of resistors
They are distinguished by four:
1. Unregulated:
A) are constants.
2. Unregulated:
A) trim;
B) variables.
3. Thermoresistors.
4. Photoresistors.
Non-adjustable permanent resistors are further divided into non-wire resistors. On the latter type, the wire is additionally wound up, so that they have a high resistivity. Permanent resistors are represented in the form of rectangles, from which there are special conclusions. The amount of permissible power dissipation is indicated inside the geometrical figure. If the resistance value is in the range from 0 to 999 ohms, the units of measurement are usually not indicated. But if this indicator is more than a thousand or a million, then the notation kOhm and MOhm, respectively, is applied. If this indicator is specified only approximately or it can change during the setting, then add *. Due to this, the types of resistors of different parameters easily differ among themselves.
Variables
We continue to consider the types of resistors. This type of device can still be called adjustable. In them, the resistance can vary from zero to nominal. They can also be non-wire. The first view is a conductive coating that is applied to the dielectric plate as an arc where a spring contact moves, which is fixed to the axis. If you want to change the resistance value, it is moved. Depending on a number of features, this parameter can vary according to these dependencies:
- Linear.
- Logarithmic.
- Indicative.
Trimmer Resistors
They do not have a protruding axis. Changing the parameters of this type of resistors is possible only with a screwdriver or an automatic / mechanical device that can perform its functions. This and the previous type of resistors are used in cases where a person must regulate their power, for example, in sound columns.
Thermoresistors
This is what semiconductor elements are called, when switched on, the indicator, such as resistance, changes from temperature to the electric circuit. As it increases, it goes down. If the temperature decreases, the resistance rises. If the process curve moves in one direction (increasing with increasing), then such an element is called a posistor.
Photoresistors
This is the name of the elements whose parameter of the parameter varies under the influence of light (and in some cases electromagnetic) radiation. As a rule, photoresistors with a positive photoelectric effect are used. Their resistance decreases when light falls on them. Photoresistors have a simple design, small dimensions and high sensitivity, which allows them to be used in photocells, counters, control systems, control and regulation devices, sensors and many other devices.
Conclusion
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