Bridge Rectifier
Diode
A full-wave rectifier that converts AC to DC using four diodes arranged in a bridge configuration. Provides a more efficient conversion than a single diode half-wave rectifier.
Schematic symbol
Diode
How bridge rectifier appears in a circuit diagram.
Types & variants
Key specs
Peak Inverse Voltage
Volt (V)Max reverse voltage a diode can withstand before breaking down. Must exceed peak AC input voltage.
Average Forward Current
Ampere (A)Max average current the rectifier can handle continuously. Must exceed circuit's DC load current.
Forward Voltage Drop
Volt (V)Voltage lost across each diode when conducting. Typically 0.7-1.1V for silicon diodes.
Max Junction Temperature
°CMax operating temperature before failure. Requires heatsinking if exceeded.
Markings
Usually printed with model number, voltage/current ratings (e.g., '600V 35A'), and polarity indicators (~ and + symbols). SMD versions may have abbreviated codes.
Standard values
Common voltage ratings: 50V, 100V, 200V, 400V, 600V, 800V, 1000V. Current ratings: 1A, 2A, 6A, 10A, 25A, 35A, 50A.
How to choose
1) Determine peak inverse voltage (AC voltage × √2). 2) Calculate average forward current (DC load current). 3) Select rectifier with ratings 20-50% higher than calculated values. 4) Consider physical size and heatsinking requirements for high current applications.
Pinout & package
Single package — 2 AC inputs, + and − outputs
Check first: The + output is usually marked with a chamfered corner or a longer lead.
4-pin packages: AC inputs (often marked with ~ or AC) and DC output (+ and -). Common packages: DB series (metal case with screw terminal), GBU series (plastic case with screw terminal), SMD packages (various sizes).
Example circuits
- AC to DC power supply conversion
- Battery charger circuits
- DC motor driver
- LED driver from AC source
- Uninterruptible power supply (UPS)
Common failures
Short circuit (diodes fail shorted), open circuit (diodes fail open), overheating (caused by excessive current or poor heatsinking). Visible signs: burnt marks, discoloration, or bulging of the package.
How to test
Set multimeter to diode test mode. Test each diode individually (AC terminals to DC terminals). Should show forward bias in one direction and open in reverse. Test with power off and disconnected from circuit.
Substitutes
Use rectifier with same or higher voltage/current ratings. Can be built from four individual diodes. Schottky diodes can be used for lower voltage drop but lower voltage rating.