 The 1N400x series was originally introduced by Motorola's Semiconductor Products Division and registered at JEDEC in 1963, as silicon power rectifiers primarily for military and industrial applications.It appeared in the Motorola "Semiconductor Data Manual" in 1965, as replacements for 1N2609 through 1N2617.The 1N540x series were announced in "Electrical Design News" in 1968, along with the now lesser known 1.5 A 1N5391 series.