How to Build a Rectifier

By Michael Logan
Capacitors, the output voltage, rectifier circuits
condensadores image by Vanesa Boullosa Lopez from Fotolia.com

Rectifiers convert alternating current to direct current. These circuits primarily comprise diodes and a capacitor, but they may also use a voltage regulator to trim the output to the desired DC voltage. There are four primary types of rectifiers: half wave, full wave, bridge, and full-wave bridge. Each has specific advantages and disadvantages. The rectifier described here is a diode bridge type that uses a zener diode to limit the output voltage to six volts, and capacitors to smooth the output to nearly perfect DC voltage.

Use the long-nose pliers to bend a right angle into each leg of all four diodes, so that you can insert the diodes vertically between two vertical rows of the breadboard.

Insert the diodes onto the breadboard so that each diode's cathode (the end with the line on it) aligns with the anode of the next diode.

Insert jumper wires to connect the diodes to each other. Connect the anode of diode 1 to the anode of diode 3. Connect the cathode of diode 1 to the anode of diode 2. Connect the cathode of diode 3 to the anode of diode 4. Connect the cathode of diode 2 to the cathode of diode 4. Connecting the diodes in this way creates a bridge rectifier.

Insert jumper wires to connect the AC transformer's output to the circuit. Connect one transformer output to the anode of diode 2. Connect the other transformer output to the anode of diode 4. If a center tap is present, do not use it.

Insert jumper wires to connect the diode bridge rectifier to the top and bottom breadboard power block positions, which you will use as the diode bridge rectifier outputs. Connect the anode of diode 1 to the set of holes along the top of the breadboard for the positive output, and the cathode of diode 2 to the bottom set of holes for the negative output.

Insert the electrolytic capacitor's positive terminal into the positive bridge output and its negative terminal into the negative bridge output. Insert the zener diode's anode into the positive bridge output and its cathode into the negative bridge output. Insert one leg of the ceramic disk capacitor into each bridge output.

Check the output with the multimeter. Set the multimeter to read DC volts. Connect the red probe to the positive bridge output and the black probe to the negative bridge output. Turn the circuit on; the multimeter should read about six volts.