## What is a Bridge Rectifier? A bridge rectifier is a power semiconductor component integrating four diodes in a single package. Based on the unidirectional conductivity of diodes, it converts Alternating Current (AC) into pulsating Direct Current (DC). It is the essential front-end component for power supplies, battery chargers, inverters, solar systems and emergency power equipmentRS. Pin marking: two `~` for AC input (no polarity); `+` and `−` for DC positive / negative output. Note: The output after rectification is pulsating DC. A filter capacitor is usually required to get smooth DC voltage. ## What does a bridge rectifier do? 1. Core function: Rectification, converting AC to DC. Mains power and transformer output are AC, while circuit boards, batteries and controllers require DC power supply. 2. Full-wave rectification uses both positive and negative AC cycles for higher efficiency than half-wave rectifiers. 3. Integrated package replaces four discrete diodes, simplifies PCB layout and improves production consistency. 4. Typical applications: power adapters, LED drivers, solar charge controllers, hand-crank emergency generators, battery chargers, industrial controls and welding machines. ## How to select a bridge rectifier 1. **Repetitive Peak Reverse Voltage (VRRM / PIV)** Peak AC voltage = RMS voltage × 1.414. Choose a rating with **1.5~2.5× safety margin**. Example: 220V AC mains, peak ≈311V → 600V or 1000V series (GBU1010, KBPC1010) are widely used. Undervoltage rating leads to breakdown easily under surge. 2. **Average Forward Current IF(AV)** It defines the continuous DC current the bridge can handle. Select a rating **1.5~2× higher than max load current**. Check surge current IFSM for capacitor inrush current at power-on. 3. **Forward Voltage Drop Vf & Die Type** - Standard silicon bridge: ~1.4V total drop, cost-effective, preferred for high voltage. - Schottky bridge: low Vf (0.4~0.6V), less heat, higher efficiency, limited voltage rating, for low-voltage high-current circuits (12V / 24V). 4. **Package & Thermal management** - SMD (MBS): ≤1A, compact for LED drivers and small power boards. - GBU / GBJ through-hole: 3A–10A, PCB mount. - KBPC square bridge: 5A–50A, mount hole, **heatsink mandatory** for industrial / high-power charging. - High-power rectifier modules: 50A+, insulated baseplate for heavy industrial inverters. > > For current >5A, enclosed housing or high ambient temperature, heatsink is required to avoid thermal damage.