How to Protect Diodes

Diodes are often used in regulator circuits.

Diodes are typically placed in an electronic circuit to control either the voltage across two points in a circuit, or as a means for limiting the directional flow of electrical current. A diode requires protection from either overvoltage or excess current situations; otherwise, the diode will fail.

One way to protect diodes from premature failure is by connecting a current-limiting resistor in series with the diode.

Things You'll Need

• One 6V DC power supply
• One 1N4001 rectifier diode
• One 100kΩ resistor
• Electrical pliers
• Electrical wire
• Electronic (rosin core) solder
• Protective eyewear

Instructions

1. Put on the protective eyewear. Cut two lengths of wire. Strip 1/2-inch of insulation from the ends of each wire.

2. Using the electrical pliers, twist together one end of the first wire to the diode cathode lead (which is designated by a line across the cathode), and solder the connection. Twist together the diode anode lead to one of the leads on the resistor and solder the connection. Twist together one end of the second wire to the free resistor lead and solder the connection.

3. Connect the free end of the first wire to the negative terminal on the power supply. Connect the free end of the second wire to the positive terminal on the power supply.

Tips & Warnings

• A resistor can be connected to either the anode or cathode lead. Either way, voltage differential across the diode will be approximately 0.7V DC, assuming that the total voltage differential in the circuit is more than 0.7 Volts.

References

• Electronic Devices; Thomas Floyd; 1996