Discrete LEDs vs. Packaged Solutions

17th August 2011

Dialight

ES Admin

0 0

Whitepaper

Designers use LEDs in three basic applications....either as a diagnostic indicator on a circuit board inside a piece of equipment, for front panel status indication, or illumination. These applications can be served by either discrete LEDs (see Fig. 16) or by packaged solutions such as DialightÕs Circuit Board Indicator (CBI) Series that combines an LED with a plastic housing (see Fig. 17). While discrete LEDs may appear to have an advantage in cost, when the total installed cost of the device is considered, the CBI solution is generally less expensive.

Diagnostic applications do not require the same level of attention to aesthetics as front panel applications, since the LED is generally viewed by a technician, and not designed to enhance the appearance of the equipment. However, the devices must still deliver consistent brightness and be positioned to ensure that the proper indicator is read. A key design goal in diagnostic applications is achieving maximum component density, so 2-mm LEDs with an integral currentlimiting resistor are employed to conserve circuit board space, which also reduces parts count. The LED is not viewed in bright light, so there is no need for a high-intensity device.

Front panel applications require the same attention to component density, with increased emphasis on aesthetic appeal. The LEDs must not only provide the basic indication or illumination function, but also complement the appearance of the host equipment, since they are located on the front panel for all to see. In many cases, the appearance of the LEDs is actually a selling feature of the end product. Consequently, uniform color, alignment, and intensity are important considerations.

Pleased download the whitepaper to continue reading.