The term **021-R** typically refers to a specific electronic component identification, most commonly associated with **Surface Mount Technology (SMT)** chip resistors or specific series of potentiometers and connectors. Below is a breakdown of the most common electronic parts carrying the "021-R" designation. --- ## 1. Vishay/BC Components: 021 ASM Series The most frequent professional reference for "021" is the **021 ASM (Axial Standard Miniature)** series of electrolytic capacitors. | Feature | Specification | | :--- | :--- | | **Type** | Aluminum Electrolytic Capacitor | | **Mounting** | Axial (leads come out of both ends) | | **Application** | Smoothing, filtering, and buffering in power supplies | | **Durability** | High reliability, often rated for 2,500 to 8,000 hours at 85°C | --- ## 2. SMD Resistor Coding: 021-R In the context of resistor marking, "R" acts as a decimal point. However, "021" is a non-standard value for standard E-series resistors. It is usually interpreted in one of two ways: ### A. Value Representation * **021-R** often signifies a **0.021 Ohm** (low-ohm) current sensing resistor. * The **R** represents the decimal point: `0.21` or `0.021` depending on the manufacturer's specific code length. ### B. Size/Package While "0201" is a standard SMD size (0.6 x 0.3 mm), "021" is sometimes used in internal cataloging for specific metric sizes. --- ## 3. Potential Connector/Hardware Reference In many industrial BOMs (Bill of Materials), **021-R** refers to a specific finish or material variant: * **R** often stands for **RoHS Compliant** (Restriction of Hazardous Substances). * It is frequently seen in **D-Sub connectors** or **RF Coaxial** parts to denote a right-angle orientation or a specific plating. --- ## Technical Identification Table If you are looking at a physical part, use this table to identify it: | Component | Visual Indicator | Likely Role | | :--- | :--- | :--- | | **Capacitor** | Blue/Black Cylinder with wires | Power filtering | | **Resistor** | Small flat black/green chip | Current sensing | | **Potentiometer** | Dial or screw adjustment | Signal tuning | | **Connector** | Metal pins/housing | Interface connection | ---