Lead mounted standard recovery rectifiers are designed for use in power supplies and other applications having need of a device with the following features:

High Current to Small Size
High Surge Current Capability
Low Forward Voltage Drop
Void−Free Economical Plastic Package
Available in Volume Quantities
Plastic Meets UL 94 V−0 for Flammability
These are Pb−Free Devices
A diode is a device which allows current flow through only one direction. That is the current should always flow from the Anode to cathode. The cathode terminal can be identified by using a grey bar as shown in the picture above.

The 1N5402 Diode has a maximum current carrying capacity of 3A and can withstand peaks up to 200A.
Common Applications of the 1N5402 Diode include:

Can be used to prevent reverse polarity problem
HV supplies
Half Wave and Full Wave rectifiers
Used as a protection device
Current flow regulators.