How to Make a Full Wave Bridge Rectifier

A crucial part of any DC power supply, a full wave bridge rectifier uses the one-way conduction of diodes to turn alternating current from a transformer into direct current. Though you can buy a rectifier bridge ready-made as a single unit, it's not difficult to make one from four diodes. Since diode characteristics vary from type to type, all four must be the same. They're inexpensive, so get four that can handle a little more current than you think you'll need from the supply.

Things You'll Need

• 4 identical diodes
• Perfboard
• 22-gauge wire
• Wire stripper
• 15- to 25-watt soldering iron
• Rosin-core solder (tin/lead or lead-free)

Instructions

1. Prepare four wires by stripping 1/2 inch of the insulation from each end with the wire strippers. "Tin" the exposed wire by heating it with the soldering iron and melting a little solder on it to coat the wire.

2. 

   Slip the diodes into the perfboard in a diamond pattern. The cathodes (marked by a stripe on the part) should all point to the right, for convenience.

3. Slip a wire through the perfboard at the point where the two leftmost anodes meet (#1 on the diagram). Twist the anode leads together with the wire and solder.

4. Slip a wire through the perfboard where the top anode meets the top cathode (#2 on the diagram). Again, twist the two leads and the wire together and solder.

5. Slip a wire through the board where the bottom anode meets the bottom cathode (#3 on the diagram). Twist the two leads and wire together and solder.

6. Slip a wire through the board where the two rightmost cathodes meet (#4 on the diagram). Twist the two leads and wire together and solder.

7. Clip excess wire and leads and discard. The bridge rectifier is finished.

Tips & Warnings

• Wire the output of a step-down transformer to the wires at points 2 and 3 on the diagram. Positive DC will be supplied at point 1 on the diagram; negative is at point 4. To build a complete power supply, you'll need a step-down transformer, filter capacitors and a voltage regulator.

• For safety, use a step-down transformer with output of 24 volts or less.

Resources

• DC Supply: Schematics