How To Read Ceramic Disc Capacitors

4 min read Jun 26, 2024
How To Read Ceramic Disc Capacitors

How to Read Ceramic Disc Capacitors

Ceramic disc capacitors are widely used in electronic circuits due to their high reliability, low cost, and compact size. However, reading the codes on these capacitors can be challenging for those who are not familiar with them. In this article, we will explain how to read ceramic disc capacitors and understand their characteristics.

Understanding the Codes

Ceramic disc capacitors typically have a three-digit code printed on them. The first two digits represent the capacitance value, and the third digit represents the multiplier.

Capacitance Value

The first two digits of the code represent the capacitance value in picofarads (pF). The value is calculated by taking the first digit as the significant figure and the second digit as the number of zeros to be added.

  • For example, if the code is "104", the capacitance value is 10,000 pF or 10 nF.
  • If the code is "472", the capacitance value is 4,700 pF or 4.7 nF.

Multiplier

The third digit of the code represents the multiplier, which is a power of 10. The multiplier is used to multiply the capacitance value to get the actual value.

  • If the code is "104" and the third digit is "1", the multiplier is 10^1, so the actual capacitance value is 10,000 pF x 10 = 100,000 pF or 100 nF.
  • If the code is "472" and the third digit is "2", the multiplier is 10^2, so the actual capacitance value is 4,700 pF x 100 = 470,000 pF or 470 nF.

Voltage Rating

The voltage rating of a ceramic disc capacitor is usually marked on the capacitor itself or on the packaging. The voltage rating is represented by a number followed by a "V" (e.g., 50V, 100V, etc.).

Tolerance

The tolerance of a ceramic disc capacitor is represented by a letter code. The most common tolerance codes are:

  • J: ±5%
  • K: ±10%
  • M: ±20%

For example, if the code is "104J", the tolerance is ±5%.

Other Markings

In addition to the code, ceramic disc capacitors may have other markings, such as:

  • Temperature Coefficient: A letter code that represents the temperature coefficient of the capacitor (e.g., "N" for -33 ppm/°C to +150 ppm/°C).
  • Certification Marks: Marks that indicate the capacitor meets specific safety standards, such as UL (Underwriters Laboratories) or ENEC (European Norms Electrical Certification).

Conclusion

Reading ceramic disc capacitors requires a basic understanding of the codes and markings on the capacitor. By following the steps outlined in this article, you can easily decode the capacitance value, voltage rating, tolerance, and other characteristics of a ceramic disc capacitor.

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