What Is a Bridge Rectifier?
1 min read
Quick answer
A bridge rectifier is a circuit that performs full-wave rectification by connecting four diodes in a bridge arrangement. It's efficient because it uses both half-cycles of the AC.
How Does It Work?
On each half-cycle of the AC input, two diodes conduct and two block. Whatever the direction, current always flows through the load the same way, so the negative half-cycles are effectively "flipped" positive.
Advantage Over Half-Wave
| Property | Half-wave | Bridge (full-wave) |
|---|---|---|
| Half-cycles used | One | Both |
| Efficiency | Low | High |
| Ripple | A lot | Less |
Getting DC With Filtering
The bridge output is still rippled; adding an electrolytic capacitor after it smooths the ripple and gives usable DC.
Where Is It Used?
In almost every AC-DC power supply, adapter and transformer-based supply. Ready-made "bridge diode" modules are also sold as a single package.
Common Mistakes
- Choosing an under-rated diode: each diode must handle the PIV and current.
- Skipping the filter capacitor: the output stays rippled.
- Grounding confusion: the bridge output isn't isolated; the common point must be chosen carefully.
Frequently Asked Questions
Why four diodes?+
Two diodes route one half-cycle and the other two route the other half-cycle, keeping current through the load always in the same direction.
Ready module or separate diodes?+
Either works; a ready module makes assembly easier, separate diodes are more flexible.
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