5mm LED

From CPFWiki

The 5mm LED is the most common and most widely-recognized type of LED.

The package is based on the standard T1¾ incandescent lamp because LEDs were first used as replacements for these small indicator lamps.

In spite of many advances in LED packaging, the 5mm endures due to its convenient dimensions and surprising versatility.

Almost all 5mm LEDs feature an optical resin housing, a leadframe, bond wire(s), and the LED chip itself. In most cases, the cathode leadframe features a tiny reflector cup to direct the light forward.

The 5mm package has a signifigant downside - its tremendous thermal resistance, typically rated at 150° C/W. Power dissipation in most 5mm LEDs must be kept below 100mW or so to prevent overheating. Most LEDs accomplish this by keeping drive current at 20mA or less.

Beacuse of the power limitations of the 5mm package, it is common to see multiple 5mm LEDs in larger flashlights.