What is Resistor?

To understand a resistor, the important thing is to understand Ohm's Law, first of all.

Ohm's law: the potential difference between two points in an electrical circuit is proportional to the current flowing between them.

If the voltage is E (V: volt) and the current is I (A: ampere), the following relationship holds.

"R" represents the coefficient of proportionality and is called resistance (electrical resistance). It is the quantity symbol and Ω (ohm) is the unit symbol. The circuit symbol is as shown in the following figure.

[Resistor circuit symbols]

When the electrical resistance is high, it is difficult for the current to flow, and when the electrical resistance is low, it is easy for the current to flow.
Using this phenomenon, resistor, as an electronic component, provide constant current flow through a circuit or current adjustment as needed. Resistors are also used to reduce or divide voltage.

As seen from above, resistors along with capacitors and inductors (coil) are the major passive components, which are essential basic components for electronic circuits.

The electrical resistance of the conductor is given by the following formula.

Electric resistance R=ρ・L/S [Ω]

・Cross-sectional area [cm²]: S
・Length [cm]: L;
・Specific resistance of material [Ω・cm]: ρ

Resistance & T.C.R. of major metals

Terminal:
Electrically and mechanically connects the resistor and the board (circuit pattern).

The electrical connection point of the resistor, where voltage and current are applied. The structure and material are configured so that it does not affect the characteristics of the resistor.

Select a resistor with a terminal structure and shape suitable for the mounting method. Surface mount components (SMD) are now the mainstream in order to improve the mounting density and reduce the mounting cost..

Coating:
Protects the resistive element and base substrate from the ambient air and mechanical stress

Example of resistor structure

• Flat Chip Resistor