Resistors｜Basic

What is a Resistor?

Resistor Basics
Resistor causes electric circuits to operate smoothly.
Outline of a Resistor
There is a broad range of resistors.
Shunt Resistors ＜Current Sence Shunt Resistors＞
Resistor used to detect circuit current are referred to as shunt resistor.
SMD Resistor ＜Chip Resistor Structure＞
This page introduces the manufacturing flow of SMD Resistor.
Chip Resistor Specifications
The external dimensions of chip resistors are typically designated using company-specific notation.
What is Rated Voltage?
Both the rated voltage and max element voltage must be considered when using a resistor.
High Power Guarantee Using Terminal Temperature Derating
Unlike conventional power derating curves based on ambient temperature, terminal temperature derating is defined by the terminal temperature of the product when power is applied.
Temperature Coefficient of Resistance①
・ Chip resistor structure
・ Chip resistor specifications
・ The resistance value of resistors changes with temperature.
Temperature Coefficient of Resistance②
Here we will explain why the temperature coefficient of resistance is specified in both positive and negative values using thick-film resistors as an example.
Temperature Coefficient of Resistance (TCR) Calculation Tool
Here we will explain how to use ROHM’s TCR Calculation Tool
Usage exceeding the rated power
It is necessary to determine whether the resistor can be used by considering the maximum power that will be applied to the product on a regular basis.
Effects of Board Design on TCR (Shunt Resistors)
Shunt resistors can measure potential differences with greater accuracy by utilizing separate wiring for current flow and voltage measurement.
Factors that Affect TCR ①
To reduce the effects of the copper foil, the sensing lines can be laid out within the shunt resistor pads.
Factors that Affect TCR ②
The thicker the copper foil on the PCB the greater the effect on the TCR of the land pattern.
Factors that Affect TCR ③
Depending on the position of the sensing lines, the TCR may differ due to the effects of the copper foil and electrodes.
Factors that Affect TCR ④
The current path also has an effect on TCR.
Notes for Resistors (PDF)
Resistors – Condition of Soldering / Land Pattern Reference (PDF)
Chip Resistor Failure Modes
This page introduces the chip resistor failure Modes such as ‘Due to Surges’ , ‘Due to Solder Cracks’ and ‘Due to Resistor Sulfuration’.
Current Sense Resistor ＜Advantages of Reverse-Mount Low-Ohmic Resistors＞
To provide greater power handling capability and improved heat dissipation characteristics, products with larger chip sizes and units configured with wider electrodes are typically used.
Destruction Due to Overload
Here we will describe failure cases when power (voltage) exceeding the specifications for each product is applied.
FAQ

【Download Documents】 Resistor Design Basics Every Engineer Should Know

Resistor Design Basics Every Engineer Should Know An introductory handbook on practical resistor design for current limiting, voltage division, and current sensing, with concise explanations of basic structures, key ratings, TCR, and reliability.

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electronics-basics

Resistors

Basic

What is a Resistor? ＋