The **EB2-4.5TNUL-R** is a specific model of a miniature, signal-type electromechanical relay manufactured by **NEC/TOKIN** (now part of KEMET/Yageo). It belongs to the EB2 series, which is known for its high density and surface-mount (SMD) capability. --- ### 1. Part Number Breakdown Understanding the nomenclature helps identify the specific characteristics of this component: | Code Segment | Meaning | Specification | | :--- | :--- | :--- | | **EB2** | Series Name | Miniature Signal Relay (Surface Mount) | | **4.5** | Coil Voltage | 4.5 Volts DC | | **T** | Type | Latching Type (Double Coil) | | **NUL** | Certification | UL/CSA Recognized (Standard Type) | | **-R** | Packaging | Tape and Reel (For automated assembly) | --- ### 2. Technical Specifications The EB2-4.5TNUL-R is designed for precision switching in telecommunications and instrumentation. #### Electrical Characteristics * **Contact Form:** 2 Form C (DPDT - Double Pole Double Throw). * **Contact Rating:** Maximum 30W / 62.5VA. * **Max Switching Voltage:** 220V DC / 250V AC. * **Max Switching Current:** 2 Amps. * **Coil Resistance:** ~145 $\Omega$ (approximate for 4.5V latching coil). * **Nominal Operating Power:** ~140 mW. #### Physical Characteristics * **Mounting Type:** Surface Mount (SMD). * **Footprint:** Compact size (approx. 14mm x 9mm). * **Lead Shape:** Gull-wing leads for easy soldering and inspection. --- ### 3. Key Features * **Latching Mechanism:** Unlike standard relays that require continuous power to stay "on," this is a **double-coil latching relay**. One coil "sets" the state, and the other "resets" it. It consumes power only during the switching transition, making it ideal for battery-powered devices. * **High Reliability:** Designed for low-level signal switching with gold-overlay silver alloy contacts. * **High Breakdown Voltage:** Offers excellent isolation between the coil and the contacts. --- ### 4. Common Applications Due to its small size and latching nature, it is frequently used in: 1. **Telecommunications:** Switching signal lines in PBX or modems. 2. **Test & Measurement:** Routing signals in automated test equipment (ATE). 3. **Medical Electronics:** Low-power switching in portable diagnostic tools. 4. **Audio Equipment:** Signal routing where minimal interference is required. ---