Capacitors often have their value printed on them. This value is usually given in picofarads (pF), nanofarads (nF), or microfarads (µF). However, due to space constraints, these values are often written in a shorthand notation.This article will explain in detail the meaning of different abbreviations on capacitors and how to correctly read the capacitance value.
How to Read Capacitance Value?
Capacitance value on a capacitor is typically denoted by a series of numbers and possibly a letter. This code is a shorthand way to write the capacitance value, and possibly the tolerance, of the capacitor. The coding system is based on a standard set by the Electronic Industries Alliance (EIA).
The first two digits of the code represent the significant figures of the capacitance value. The third digit represents the multiplier, indicating the number of zeros that follow the first two digits. This value is given in picofarads (pF). For example, a capacitor with the code "104" would have a capacitance value of 100,000 pF. This is because the first two digits "10" represent the significant figures, and the third digit "4" represents the number of zeros following, giving us "100000".
If there is a letter following the numbers, it represents the tolerance of the capacitor, which is the range within which the actual capacitance value may deviate from the marked value. For example, a "K" indicates a tolerance of ±10%, and a "M" indicates a tolerance of ±20%. So, a capacitor marked "104K" would have a capacitance value of 100,000 pF, or 0.1 μF, with a tolerance of ±10%.
Reading Three Digit Capacitor Codes
A three-digit code on a capacitor is a common way of marking the capacitance value. Here's how it works:
The first two digits are the significant figures. These are the two numbers that the value of the capacitor starts with. The third digit is the multiplier. It indicates the number of zeros that should be added after the significant figures. This value is in picofarads (pF).
For example, if you have a capacitor with a three-digit code of "104", here's how you read it:
The first two digits "10" are the significant figures.
The third digit "4" is the multiplier, meaning you add four zeros after the significant figures.
So, "104" means the capacitor has a value of 10 × 104 pF, or 100,000 pF.
| Three-Digit Code | Picofarads (pF) | Nanofarads (nF) | Microfarads (µF) |
|---|
| 101 | 100 | 0.1 | 0.0001 |
| 102 | 1,000 | 1 | 0.001 |
| 103 | 10,000 | 10 | 0.01 |
| 104 | 100,000 | 100 | 0.1 |
| 105 | 1,000,000 | 1,000 | 1 |
| 222 | 2,200 | 2.2 | 0.0022 |
| 223 | 22,000 | 22 | 0.022 |
| 224 | 220,000 | 220 | 0.22 |
| 474 | 470,000 | 470 | 0.47 |
| 334 | 330,000 | 330 | 0.33 |
Reading Two Digit Capacitor Codes
Two-digit code capacitors are less common than three-digit ones, but they do exist. Typically, two-digit codes are used for capacitors with values less than 10 picofarads (pF).
Here's how you read a two-digit code:
The first digit is the significant figure.
The second digit is the multiplier, indicating the number of zeros to follow.
This value is also in picofarads (pF).
For example, a capacitor with a two-digit code of "47" would have a value of 4 × 107 pF, or 40,000,000 pF. However, such a high value is not practical for a capacitor, so in reality, a "47" code would typically indicate a capacitor with a value of 47 pF.
Capacitor Tolerance Code
The fourth character (which is typically a letter) in the code on a capacitor indicates the tolerance of the capacitor, which is the allowable range of deviation from the nominal value. The nominal value is the value that is printed on the capacitor, and the actual capacitance of the capacitor can vary within the range defined by the tolerance.
Here's a quick reference for the tolerance codes you listed:
| Letter | Tolerance |
|---|
| D | ±0.5 pF |
| F | ±1% |
| G | ±2% |
| H | ±3% |
| J | ±5% |
| K | ±10% |
| M | ±20% |
| P | +100%, -0% |
| Z | +80%, -20% |
For example, a capacitor with the code "102K" would have a nominal value of 1,000 pF (or 1 nF), and the actual capacitance could vary by ±10% from this value due to the "K" tolerance code. This means the actual capacitance could be anywhere between 900 pF and 1,100 pF.
Capacitor Code Example
Example 1: 102M capacitor value
A capacitor marked with the code "102M" would be interpreted as follows:
The first two digits "10" are the significant figures.
The third digit "2" represents the multiplier, indicating the number of zeros to follow in picofarads (pF).
Therefore, a capacitor with the code "102" would have a value of 10 × 102 pF, or 1000 pF, which is also equivalent to 1 nanofarad (nF).
The "M" at the end represents the tolerance of the capacitor. In this case, "M" indicates a tolerance of ±20%. This means the actual capacitance of the capacitor can vary by up to 20% from the marked value. So, the actual capacitance could be anywhere between 800 pF and 1200 pF.
Example 2: 473M Capacitor value
A capacitor marked with the code "473M" would be interpreted as follows:
The first two digits "47" are the significant figures.
The third digit "3" represents the multiplier, indicating the number of zeros to follow in picofarads (pF).
Therefore, a capacitor with the code "473" would have a value of 47 × 103 pF, or 47000 pF, which is also equivalent to 47 nanofarads (nF).
The "M" at the end represents the tolerance of the capacitor. In this case, "M" indicates a tolerance of ±20%. This means the actual capacitance of the capacitor can vary by up to 20% from the marked value. So, the actual capacitance could be anywhere between 37.6 nF and 56.4 nF.
Example 3: 102K Capacitor value in uf
A capacitor marked with the code "102K" would be interpreted as follows:
The first two digits "10" are the significant figures.
The third digit "2" represents the multiplier, indicating the number of zeros to follow in picofarads (pF).
Therefore, a capacitor with the code "102" would have a value of 10 × 102 pF, or 1000 pF, which is also equivalent to 1 nanofarad (nF).
The "K" at the end represents the tolerance of the capacitor. In this case, "K" indicates a tolerance of ±10%.
To convert this value to microfarads (uF), remember that 1 uF equals 1,000,000 pF. So, 1000 pF is equal to 0.001 uF or 1 nF.
Therefore, the value of a "102K" capacitor is 0.001 uF (or 1 nF) with a tolerance of ±10%.
Example 4: 472K Capacitor value
The code "472K" on a capacitor is interpreted as follows:
The first two digits "47" are the significant figures.
The third digit "2" indicates the number of zeros that follow, which gives us "4700" in picofarads (pF).
Converting picofarads (pF) to microfarads (μF): 1 μF = 1,000,000 pF, so 4700 pF = 0.0047 μF.
The letter "K" represents a tolerance of ±10%.
Therefore, "472K" means a capacitance of 0.0047 μF with a tolerance of ±10%.
Example 5: 473 Capacitor value
The code "473" on a capacitor is interpreted as follows:
The first two digits "47" are the significant figures.
The third digit "3" indicates the number of zeros that follow, which gives us "47000" in picofarads (pF).
Converting picofarads (pF) to microfarads (μF): 1 μF = 1,000,000 pF, so 47000 pF = 0.047 μF.
Therefore, "473" means a capacitance of 0.047 μF. Note that without a letter at the end, the tolerance is not specified