Identify 2 pin plc

The component you have is probably one of:

Tantalum Capacitor
These are usually either yellow or black in colour. The capacitance is usually printed on the top. A stripe at one end identifies the positive end.

Diode
These usually have small metal legs which loop round underneath the two ends. They are typically black in colour with a silver or white stripe at one end. The stripe is the cathode end.