What Is the 1N4148? Fast Signal Diode: Specs and Uses
The 1N4148 is the most common small-signal / fast-switching diode. With a very short reverse recovery (~4 ns), 100 V reverse voltage and 200 mA forward current, it is used for signal steering, clamping and logic circuits. It is not for power rectification (use the 1N4007); for low loss use a Schottky like the 1N5819. The banded side is the cathode.
The 1N4148 is the most common small-signal / fast-switching diode. With its small glass DO-35 body and very short recovery time (trr), it is a standard part in signal and logic circuits. For the concept, see what is a diode.
What is the 1N4148 used for?
Signal steering/switching, voltage clamping, logic "AND/OR" gates, low-current freewheeling, detectors and general protection. Its high speed makes it suitable for signal work where slow power diodes such as the 1N4007 are not.
Key electrical specifications
| Parameter | Typical value |
|---|---|
| Type | Small-signal / fast-switching diode |
| Reverse voltage (VR) | 100 V |
| Forward current (average) | 200 mA |
| Reverse recovery (trr) | ~4 ns (very fast) |
| Body | DO-35 (glass) |
The banded (striped) side of the diode is the cathode.
Limitations
- Low current (200 mA); not for power rectification → use the 1N4007.
- Forward drop ~0.7 V; if you need low loss, use a Schottky (1N5819).
1N4148 equivalents and alternatives
- 1N914: a nearly identical equivalent.
- BAT85 / BAT54: lower-loss Schottky alternatives.
- LL4148: the SMD (MELF) version.
Find it in our catalog
To compare price and stock for the 1N4148 and its alternatives, use the 1N4148 search.