Seven Segment Display
These displays are logic compatible with a max drive current of 20mA and a forward voltage drop of about 2V.
Calculating LED Resistor Values
At an operating voltage of 5V, a series current limiting resistor of 150 ohm will provide max brightness if driving these displays in a static mode rather than in a a more typical multiplexing mode.
When you are using displays with multiple digits in a multiplexed mode where each digit is only lit for a portion of the time, the maximum allowable current can be greater than 20mA and can go up to as high as 60 mA. In that case, you generally want to drive the display with more current since each digit in the display is on only a portion of the time and will therefore appear dimmer than if the digit was being driven constantly on. For that application, a resistor value of 50 ohms will provide max brightness. Values in the range of 75-91 generally work pretty well when max brightness is not required.
TECHNICAL SPECIFICATIONS
| Display Type | 7-Segment (x 4) | |
| Color | Red | |
| Type | Common Cathode (CC) | |
| Maximum Ratings | ||
| IF | Maximum Forward Current | 20mA (constant current per segment) |
| VF | Maximum Forward Voltage | 2V (Typical) |
| Package Type | Encapsulated plastic body, 12-lead, through hole | |
| Dimensions | ||
| Character Height | 14.2mm (0.56″) | |
| Module (L x W x H) | 51 x 19 x 8mm (2 x 0.75 x 0.31) |