The 1N4148 is a standard silicon switching signal diode. This is a high-speed switching diode fabricated in planar technology and encapsulated in hermetically sealed leaded glass SOD27 (DO-35) packages.
https://www.fairchildsemi.com/datasheets/1N/1N914.pdf
https://www.fairchildsemi.com/datasheets/1N/1N914.pdf
