The **BK/PCC-3-R** is a high-performance subminiature fuse manufactured by **Eaton (formerly Bussmann)**. It belongs to the PC-Tron® series, which is specifically designed for circuit protection in compact electronic environments. --- ### ## Technical Specifications Below are the primary electrical and mechanical characteristics of the device: | Feature | Specification | | :--- | :--- | | **Series** | PC-Tron® (PCC) | | **Current Rating** | 3 Amperes | | **Voltage Rating (AC)** | 250 VAC | | **Voltage Rating (DC)** | 125 VDC | | **Interrupt Rating** | 50A @ 250VAC / 10,000A @ 125VAC | | **Mounting Type** | Through-Hole (Radial Leads) | | **Response Time** | Fast-Acting | | **Body Material** | High-temperature plastic | | **Lead Finish** | Tin-plated copper | --- ### ## Key Components & Design Features #### 1. Radial Lead Configuration The "PCC" designation indicates that this fuse has **radial leads**. Unlike traditional glass tube fuses, these are soldered directly into a Printed Circuit Board (PCB). The "R" in the suffix typically denotes RoHS compliance. #### 2. Fast-Acting Response The fuse is designed to "open" (blow) very quickly when an overcurrent condition occurs. This is critical for protecting sensitive semiconductor components like integrated circuits (ICs) and transistors that cannot withstand prolonged surges. #### 3. High Interrupting Capacity Despite its small size, it has a significant interrupting rating at 125VAC (up to 10,000 Amps), meaning it can safely handle high-energy faults without exploding or causing a fire. --- ### ## Common Applications The BK/PCC-3-R is widely used in industrial and consumer electronics where space is at a premium: * **Power Supplies:** Protecting the primary and secondary stages of AC/DC converters. * **Telecommunications:** Line cards and networking equipment. * **Industrial Controls:** Protecting PLCs and sensor interfaces. * **Consumer Electronics:** High-end chargers and appliances. --- ### ## Code Example: Circuit Protection Verification When designing a PCB for this part, engineers must ensure the trace width can handle the current before the fuse blows. ```python # Simple calculation for required trace width (Internal Trace) # Based on IPC-2221 standards def calculate_trace_width(current_amps, temp_rise=10, thickness_oz=1): # Constants for internal traces k = 0.024 b = 0.44 c = 0.725 # Area in square mils area = (current_amps / (k * (temp_rise**b)))**(1/c) # Width = Area / (Thickness in mils) # 1oz copper is approx 1.37 mils width_mils = area / (thickness_oz * 1.37) return round(width_mils, 2) # For a 3A fuse, we might design for 4A to avoid nuisance heating print(f"Required Trace Width: {calculate_trace_width(4)} mils") ```