The 1N4001 series (or 1N4000 series) is a family of popular 1 A (ampere) general-purpose silicon rectifier diodes commonly used in AC adapters for common household appliances. Blocking voltage varies from 50 to 1000 volts. This diode series is available in DO-41 axial package, SMA and MELF surface mount packages.
The 1N5400 series is a similarly popular series for higher-current 3 A applications. These diodes are typically available in the larger DO-201AD axial package to dissipate heat better.
1N400x general-purpose diodes Wikipedia
These are fairly low-speed rectifier diodes, being inefficient for square waves of more than 15 kHz. These devices are widely used and recommended.
The series was second sourced by many manufacturers. The 1N4000 series were in the Motorola Semiconductor Data Manual in 1965, as replacements for 1N2609 through 1N2617. The 1N5400 series were announced in Electrical Design News in 1968, along with the now lesser known 1.5 A 1N5391 series.
The table below shows the maximum repetitive reverse blocking voltages of each of the members of the 1N4000 and 1N5400 series.
In the version of these components manufactured for Fairchild Semiconductor in Suzhou, the silicon chip that rectifies the current weighs just 880 micrograms.