Understanding Capacitor Value Codes

Capacitors often use a numerical code to indicate their capacitance value in picofarads (pF) along with their tolerance. The value is usually given as two significant digits followed by a multiplier. For example, a code “104” means the capacitance is 10 × 10⁴ pF, which equals 100,000 pF or 100 nF.

Understanding these codes is essential for designing and troubleshooting circuits. The tolerance, expressed as a percentage, indicates the allowable variation from the stated value, ensuring accurate operation in sensitive applications.

Example Calculations

Example 1:

Code: “104”

• Digit 1 = 1
• Digit 2 = 0
• Multiplier = 10,000

Capacitance: 10 × 10,000 = 100,000 pF = 100 nF
Tolerance: ±20% (if tolerance is 20%).

Example 2:

Code: “222”

• Digit 1 = 2
• Digit 2 = 2
• Multiplier = 100

Capacitance: 22 × 100 = 2,200 pF = 2.2 nF
Tolerance: ±10% (if tolerance is 10%).

Example 3:

Code: “681”

• Digit 1 = 6
• Digit 2 = 8
• Multiplier = 10

Capacitance: 68 × 10 = 680 pF
Tolerance: ±5% (if tolerance is 5%).