The code **331M** is a standard marking used for electronic components, most commonly found on **Ceramic Disc Capacitors** and sometimes on **Inductors**. ### 1. Decoding the Value The alphanumeric code follows a standard "three-digit" convention where the first two digits are significant figures and the third is the multiplier. | Part Segment | Value | Description | | :--- | :--- | :--- | | **33** | 33 | The base value (significant digits) | | **1** | $10^1$ (10) | The multiplier (number of zeros to add) | | **M** | ±20% | The tolerance rating | **Calculation:** $33 \times 10 = 330$ --- ### 2. Common Component Types #### A. Ceramic Disc Capacitors For capacitors, the unit of measurement is always **Picofarads (pF)**. * **Value in pF:** 330 pF * **Value in nF:** 0.33 nF * **Value in µF:** 0.00033 µF * **Tolerance (M):** ±20%. This means the actual capacitance can range from 264 pF to 396 pF. #### B. Inductors If the code appears on a molded or power inductor, the unit of measurement is typically **Microhenries (µH)**. * **Value:** 330 µH * **Tolerance (M):** ±20%. --- ### 3. Specifications Table | Feature | Specification | | :--- | :--- | | **Base Value** | 330 | | **Unit (Capacitor)** | pF (Picofarads) | | **Unit (Inductor)** | µH (Microhenries) | | **Tolerance Code** | M (Standard ±20%) | | **Dielectric (Typical)** | Y5P, Z5U, or X7R (for capacitors) | --- ### 4. Summary of Other Tolerance Codes While "M" stands for ±20%, you may encounter these other common letters on similar parts: * **J:** ±5% * **K:** ±10% * **Z:** +80% / -20% ---