The 1N4148 is a standard silicon switching signal diode. It is one of the most popular and long-lived switching diodes because of its dependable specifications and low cost. Its name follows the JEDEC nomenclature. The 1N4148 is useful in switching applications up to about 100 MHz with a reverse-recovery time of no more than 4 ns.
1N4148 signal diode Wikipedia
The 1N4148 comes in a DO-35 glass package for through-hole mounting, which is useful for breadboarding of circuits. Surface mount devices are available: LL4148 in MiniMELF package, 1N4148W in SOD-123 package, 1N4148WS in SOD-323 package, 1N4148X in SOD-523 package. Some surface mount packages are marked with "T4" text.
As the most common mass-produced switching diode, the 1N4148 replaced the older 1N914. They differ mainly in their leakage current specification at 25°C: 25 nA @ -20V vs. 5 µA @ -75V. with maximum leakage for both at 150°C to be 50 µA @ -20V. Today manufacturers produce the 1N4148 and sell it as either part number. It was second-sourced by many manufacturers; Texas Instruments listed their version of the device in an October 1966 data sheet. These device types have an enduring popularity in low-current applications.VRRM = 75-100 V — maximum repetitive reverse voltage
IO = 75-200 mA — average rectified forward current
IF = 200-300 mA — maximum direct forward current
VF = 1.0 V at 10 mA.
IFSM = 1.0 A (pulse width = 1 s), 4.0 A (pulse width = 1 µs) — non-repetitive peak forward surge current
PD = 500 mW — power dissipation
TRR < 4 ns — reverse-recovery time