1N4148

The 1N4148 is a small-signal silicon switching diode that is widely used in electronic circuits for fast switching, signal processing, and rectification tasks. It is typically packaged in a glass axial package (DO-35) and is available from numerous manufacturers, sometimes sold as 1N4148 or 1N4148W variants.

Electrical characteristics define it as a general-purpose fast diode. It has a reverse-voltage rating of about 100 V and a maximum average forward current of roughly 150 mA, with a peak forward surge current around 2 A. Power dissipation is commonly specified near 500 mW, and the maximum junction temperature is about 150°C. The diode is characterized by a short reverse-recovery time, typically around 4 nanoseconds, which supports high-speed switching. Its junction capacitance is small, typically in the range of 2 to 4 pF at zero bias, which helps minimize stray effects in high-frequency circuits.

Applications for the 1N4148 include signal demodulation, clipping and clamping, protection in logic circuits, and other fast-switching roles where a small, fast diode is suitable. It is not intended for high-power or high-current applications. Because it is so common and inexpensive, the 1N4148 is often used as a general-purpose reference diode or as a replacement in many low-current switching tasks, though exact performance should be confirmed from the specific manufacturer’s datasheet for a given batch or variant.