What is a Precision resistor?- Precision resistor color code guide

What is a Precision resistor?

A precision resistor is a normal resistor with near accurate Ohmic values. Technically they have very low tolerance value as compared to the normal resistors.
The lower the value of tolerance of the resistor shows the lower deviation from resistor value and higher the value of tolerance the higher the deviation from the actual standard value.
The Precision resistor is also called a film resistor or foil resistor.

The tolerance value is indicated in percentage (%).

You can say that if the tolerance value of the resistor is below 1% it can be classified under precision resistor, they have the tolerance in the range of 0.005%, 0.025%, 0.1%, 0.01%, etc

There are some other factors that are also considered while considering the precision in the resistance that will be discussed below in detail.
The resistance with the tolerance value 10%, 20%, 5% does not fall under the Precision resistor.

Ultra precision
±0.005%

Precision
±0.01%
±0.02%
±0.025%
±0.05%
±0.1%
±0.25%
±0.5%
±1%

General
±3%
±5%
±10%
±20%

Observe the difference among various tolerance values of the resistor and resultant value of resistor:

10k resistor 10% tolerance = 9000 to 11000 Ω
10k resistor 5% tolerance = 9500 to 10500 Ω
10k resistor 1% tolerance = 9900 to 10100 Ω
10k resistor 0.005% tolerance = 9999.5 to 10000.5 Ω

From the above observation, we can say that the nominal value of the resistor is between this two range and tolerance value play a great role if accuracy matters in your circuit.

Important factors of precision resistors:

• Technology involved: Wire-wound, Metal Film, Metal Foil, Bare Metal, Thin Film. All technology gives different results in resistor performance.

• Temperature coefficient ( ppm/°C ): It is the amount the Resistor value changes for every 1°C change in temperature.
  110 ppm/°C means the Resistance increases 110 Ohms for every 1M Ohm resistance for each degree rise in temperature. Or say ratio wise for other values, 11 ohms for every 100k or 1.1 ohm every 10k.
• Operating temperature: It indicates the operating temperature range of the resistor in which it remains stable, also can work without being damaged.
• Power rating: It indicates the power handling capacity of a resistor without being damaged.

 

Application of Precision resistor:

• Electronic weighing machine/ scales: Electronic weighing machine is two way the object and this purpose should be must be fulfilled with the accuracy, Precision resistor provide that accuracy in the circuit of the weighing machine.
• Audio application/ low noise amplifier: Audio device is one of the widely used devices that requires precise very low noise resistors and other components. Highly stable and linear response of Precision resistor Ideal for audio application.
• Commercial aviation industry: Highly accurate value of onboard instruments in the airplane is necessary as it operates and handles the critical conditions of such a Mammoth machine.
• Measuring instruments and meters: Digital multi-meters, LC meters, audio meters, altimeters, and all sort of measuring instruments install Precision resistors who has to give the measured value of a particular physical or electrical condition.

 

Precision Resistor color code: 5 band resistor color code and 6 band resistor color code

5 band and 6 band resistor color Code is generally used to indicate the color code of Precision resistors, the following table showing 5/ 6 band resistor color code: