1N400x

1N400x refers to a family of general-purpose silicon rectifier diodes used for low-frequency rectification. They are rated for 1 A average rectified current and are available in a series of devices labeled 1N4001 through 1N4007. Each variant shares a common construction but differs in maximum repetitive reverse voltage (VRRM): 1N4001 (50 V), 1N4002 (100 V), 1N4003 (200 V), 1N4004 (400 V), 1N4005 (600 V), 1N4006 (800 V), and 1N4007 (1000 V).

The diodes are commonly housed in a DO-41 axial package with leads at each end and are designed to handle an average rectified current of 1 A. They support a peak surge current (IFSM) typically around 30 A for a brief interval (8.3 ms half-sine). The forward voltage drop is usually about 0.7 V at rated current, while the reverse recovery time is relatively slow compared with fast-switching diodes, making them less suitable for high-frequency switching.

Typical applications include rectification in power supplies, battery chargers, and general-purpose rectifier roles in consumer electronics and hobby projects. They are robust, inexpensive, and widely available from multiple manufacturers, often used in bridge rectifier configurations.

Operational considerations include avoiding operation at or near the VRRM rating for extended periods, ensuring adequate derating and heat dissipation, and selecting faster or lower-forward-drop diodes (such as Schottky or fast-recovery types) when used in high-frequency or efficiency-critical circuits.