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The metric codes still represent the dimensions in mm, even though the imperial size codes are no longer aligned. Problematically, some manufacturers are developing metric 0201 components with dimensions of 0.25 mm × 0.125 mm (0.0098 in × 0.0049 in), [ 31 ] but the imperial 01005 name is already being used for the 0.4 mm × 0.2 mm (0.0157 in ...
The light from white LED lamps and LED strip lights is usually provided by industry standard surface-mounted device LEDs (SMD LEDs). [2] Non-SMD types of LED lighting also exist, such as COB (chip on board) and MCOB (multi-COB). Surface-mounted device LED modules are described by the dimensions of the LED package. A single multicolor module may ...
The reference designator usually consists of one or two letters followed by a number, e.g. C3, D1, R4, U15. The number is sometimes followed by a letter, indicating that components are grouped or matched with each other, e.g. R17A, R17B. The IEEE 315 standard contains a list of Class Designation Letters to use for electrical and electronic ...
These handling difficulties prompted development of alternative SMT packages for common MELF components (like diodes) where the power handling capability needed to be similar to MELF components (superior to low-power 0805/0603, etc. SMT components) but with improved automated pick-and-place handling characteristics. [3]
IEC 62090 Product package labels for electronic components using bar code and two-dimensional symbologies; IEC 62091 Low-voltage switchgear and control gear – Controllers for drivers of stationary fire pumps; IEC 62093 Balance-of-system components for photovoltaic systems – Design qualification natural environments
The same code marked on different packages or on devices from different manufacturers can translate to different devices. Many of these codes, used because the devices are too small to be marked with more traditional numbers used on larger packages, correlate to more familiar traditional part numbers when a correlation list is consulted.
Overdriving an LED in high ambient temperatures may result in overheating the LED package, eventually leading to device failure. An adequate heat sink is needed to maintain long life. This is especially important in automotive, medical, and military uses where devices must operate over a wide range of temperatures, and require low failure rates.
Reverse bias: Although the LED is based on a diode junction and is nominally a rectifier, the reverse-breakdown mode for some types can occur at very low voltages and essentially any excess reverse bias can cause immediate degradation, and may lead to vastly accelerated failure. 5 V is a typical maximum reverse bias voltage specification for ...