It’s a 1N5408 3A diode. It is a general purpose rectifier diode which is generally use in DC-DC converters, AC-DC Converters, Voltage switching, Clamping circuit, Power Supply, Power supply, Voltage regulators, Rectifier. It has average forward current 3A and forward voltage drop is 1V and non repetitive peak current is 200A, it’s peak reverse current is 10uA. SPECIFICATION Diode type: General purpose rectifier diode Diode number: 1N5408 Average forward current is 3A Forward Voltage drop is 1V @3A Non-repetitive Peak  current is 200A Peak Reverse current is 10uA. Repetitive reverse voltage is 1000V