1N4148 signal diode

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A schematic symbol for a diode Diode symbol.svg
A schematic symbol for a diode
1N4148 diodes in DO-35 glass-encapsulated axial lead package Diode 1n4148.jpg
1N4148 diodes in DO-35 glass-encapsulated axial lead package

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.

Silicon Chemical element with atomic number 14

Silicon is a chemical element with symbol Si and atomic number 14. It is a hard and brittle crystalline solid with a blue-grey metallic lustre; and it is a tetravalent metalloid and semiconductor. It is a member of group 14 in the periodic table: carbon is above it; and germanium, tin, and lead are below it. It is relatively unreactive. Because of its high chemical affinity for oxygen, it was not until 1823 that Jöns Jakob Berzelius was first able to prepare it and characterize it in pure form. Its melting and boiling points of 1414 °C and 3265 °C respectively are the second-highest among all the metalloids and nonmetals, being only surpassed by boron. Silicon is the eighth most common element in the universe by mass, but very rarely occurs as the pure element in the Earth's crust. It is most widely distributed in dusts, sands, planetoids, and planets as various forms of silicon dioxide (silica) or silicates. More than 90% of the Earth's crust is composed of silicate minerals, making silicon the second most abundant element in the Earth's crust after oxygen.

Diode electronic component

A diode is a two-terminal electronic component that conducts current primarily in one direction ; it has low resistance in one direction, and high resistance in the other. A diode vacuum tube or thermionic diode is a vacuum tube with two electrodes, a heated cathode and a plate, in which electrons can flow in only one direction, from cathode to plate. A semiconductor diode, the most common type today, is a crystalline piece of semiconductor material with a p–n junction connected to two electrical terminals. Semiconductor diodes were the first semiconductor electronic devices. The discovery of asymmetric electrical conduction across the contact between a crystalline mineral and a metal was made by German physicist Ferdinand Braun in 1874. Today, most diodes are made of silicon, but other materials such as gallium arsenide and germanium are used.

JEDEC standards organization

The JEDEC Solid State Technology Association is an independent semiconductor engineering trade organization and standardization body.



As the most common mass-produced switching diode, the 1N4148 replaced the older 1N914. They differed mainly in their leakage current specification, however, today most manufacturers list common specifications. For example, Vishay [1] [2] lists the lame leakage current for both parts:

In electronics, leakage may refer to a gradual loss of energy from a charged capacitor. It is primarily caused by electronic devices attached to the capacitors, such as transistors or diodes, which conduct a small amount of current even when they are turned off. Even though this off current is an order of magnitude less than the current through the device when it is on, the current still slowly discharges the capacitor. Another contributor to leakage from a capacitor is from the undesired imperfection of some dielectric materials used in capacitors, also known as dielectric leakage. It is a result of the dielectric material not being a perfect insulator and having some non-zero conductivity, allowing a leakage current to flow, slowly discharging the capacitor.

Today manufacturers produce the 1N4148 and sell it as either part number. [3] It was second-sourced by many manufacturers; Texas Instruments listed their version of the device in an October 1966 data sheet. [4] These device types have an enduring popularity in low-current applications. [5] [6]

In the electronics industry, a second source is a company that is licensed to manufacture and sell components originally designed by another company.

Texas Instruments American company that designs and makes semiconductors

Texas Instruments Inc. (TI) is an American technology company that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globally. Its headquarters are in Dallas, Texas, United States. TI is one of the top ten semiconductor companies worldwide, based on sales volume. Texas Instruments's focus is on developing analog chips and embedded processors, which accounts for more than 80% of their revenue. TI also produces TI digital light processing (DLP) technology and education technology products including calculators, microcontrollers and multi-core processors. To date, TI has more than 43,000 patents worldwide.

The JEDEC registered part numbers 1N4148 and 1N914 are diodes in an axial package. Diodes with similar properties are available in surface-mount packages.

Surface-mount technology method for producing electronic circuits

Surface-mount technology (SMT) is a method for producing electronic circuits in which the components are mounted or placed directly onto the surface of printed circuit boards (PCBs). An electronic device so made is called a surface-mount device (SMD). In industry, it has largely replaced the through-hole technology construction method of fitting components with wire leads into holes in the circuit board. Both technologies can be used on the same board, with the through-hole technology used for components not suitable for surface mounting such as large transformers and heat-sinked power semiconductors.

Through-hole package
Surface-mount packages

Note: Some surface-mount packages are marked with "T4" text. [10] [11]


Absolute maximum ratings (stress ratings, consult datasheet for recommended ratings) [7]

Electrical and thermal characteristics [7]

See also

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  1. 1N914 Datasheet; DO-35 Package; Vishay.
  2. 1 2 1N4148 Datasheet; DO-35 Package; Vishay.
  3. Michael Predko (2004). 123 robotics experiments for the evil genius. McGraw-Hill Professional. p. 93. ISBN   978-0-07-141358-9.
  4. The Transistor and Diode Data Book, Texas Instruments Incorporated, publication no. CC-413 71243-73-CSS, no date, page 10-34
  5. Jonathan Oxer; Hugh Blemings (2009). Practical Arduino: Cool Projects for Open Source Hardware. Apress. p. 10. ISBN   978-1-4302-2477-8. Small "signal" diodes like the venerable 1N4148/1N914 can cope with about 200mA...
  6. Michael Gasperi; Philippe E. Hurbain; Philippe Hurbain (2009). Extreme NXT: Extending the Lego Mindstorms NXT to the Next Level (2nd ed.). Apress. p. 211. ISBN   978-1-4302-2453-2. You could use a 1N4002, but the 1N4148 is smaller and more appropriate for the current...
  7. 1 2 3 1N4148 Datasheet; DO-35 Package; Fairchild.
  8. 1N4148 Datasheet; DO-35 Package; Kingtronics.
  9. LL4148 Datasheet; MiniMELF Package; Kingtronics.
  10. 1 2 1N4148W Datasheet; SOD-123 Package; Diodes Inc.
  11. 1 2 1N4148W Datasheet; SOD-123 Package; MCC.
  12. 1N4148W Datasheet; SOD-123 Package; Vishay.
  13. 1N4148WS Datasheet; SOD-323 Package; Diodes Inc.
  14. 1N4148WS Datasheet; SOD-323 Package; Vishay.
  15. 1N4148WT Datasheet; SOD-523 Package; Diodes Inc.
  16. 1N4148X Datasheet; SOD-523 Package; MCC.
  17. "1". The Semiconctor Data Library (Fourth ed.). Motorola Semiconductor Products, Inc. 1973. p. 73.

Further reading

Historical Databooks