20CTQ040
2917 (7343 Metric)
39504278-20CTQ040
20A, 40V, TO-220AB,SCHOTTKY RECT
RATED voltage is the voltage on the nameplate - the "design point" for maximum power throughput and safe thermal operation.
The operating temperature is the range of ambient temperature within which a power supply, or any other electrical equipment, operate in. This ranges from a minimum operating temperature, to a peak or maximum operating temperature, outside which, the power supply may fail.
the frequency with which an engineered system or component fails, expressed in failures per unit of time. It is usually denoted by the Greek letter λ (lambda) and is often used in reliability engineering.
the distance between two baselines of lines of type. The word 'leading' originates from the strips of lead hand-typesetters used to use to space out lines of text evenly. The word leading has stuck, but essentially it's a typographer's term for line spacing.