NEW PRODUCTS – Red, Yellow or Green 7-segment clock display – 1.2 digit height. I like big seven-segment displays and I cannot lie! Design a clock, timer or counter into your next project using our pretty, candy-bar sized 4-digit seven-segment display. These bright crisp displays are good for adding numeric output. Besides the four 7-segments, there are decimal points on each digit, a top right dot (perhaps useful as a degrees symbol) and two sets of colon-dots (good for time-based projects).
These are ultra bright 400mcd per segment! Each segment is made of two LEDs in series for even coloring (check the datasheet for a diagram). You can drive these with less current to get the same brightness to save power, or crank them up to 20mA and have them really bright.
These displays are multiplexed, common-cathode. What that means it that you can use a 74HC595 or just 8 microcontroller pins if you can spare them to control the 8 anodes (7-seg + decimal) at about ~15mA each, and then connect NPN transistors or a TPIC6B595 to the cathodes to sink the 8*20mA = ~120mA maximum per digit.