Since the relationship between voltage, current, and resistance in any circuit is regular, we can reliably control any variable in the circuit by controlling the other two variables. Maybe the easiest variable to control in a circuit is its resistance. This can be done by changing the material, size and shape of the conductive device.
Resistors are generally made of wire or carbon and are carefully designed to maintain stable resistance values under a variety of environmental conditions. We have Glenair-121-154-20.
But unlike lamps, resistors do not produce light, but they do generate heat when a working circuit consumes electricity. Generally, however, the purpose of a resistor is not to generate usable heat, but to provide accurate resistance.
That is, the device used to provide precise resistance values in a circuit is called a resistor. Resistors are evaluated and selected based on their resistance (ohms) and heat dissipation (watts).
The resistance rating of a resistor is not determined by physical size, rated power size, and volume. The larger the resistance, the more power it can safely consume without damage. Any device that uses electricity to perform some useful task is commonly referred to as a load. Occasionally a resistance symbol is used in the schematic in place of a set of energy-consuming loads rather than the actual resistance.
Thus the above is the relevant introduction of resistance. I hope to help you, the need for electronic components of friends, welcome to consult ~