Alphanumeric Display

[SatyamBhujan]

Hi Guys. I am new to the electronic world. I am very much keen of knowing these stuffs. Can anyone help me understand what do the alphabets onboard means?

[Tien_P]

Here is a tutorial for the 7 segment LED I found online, it works similar to the alpah-numeric display.

http://www.electronics-tutorials.ws/blog/7-segment-display-tutorial.html

The CA stands for common cathode and the remaining letters are the LED reference. To figure out which pin turn on which LED segment, connect all CA pins to power and then go around and connect the other pins to ground. In attached example, you can see the A pin turns on the upper horizontal LED.

[SatyamBhujan]

Hi Tien_P

Thank you very much for the tutorial... It works.

However, when i changed to an 15 Segment - LED Alpha Numeric Display (Based on C-398G),  the same circuit never works. Why is that? See below.

[Tien_P · Accepted solution]

The pin CK tells you the display LED is a common cathode, in the previous example we used a common anode (CA).  If you look at the tutorial from my previous post, there are figures showing you the internal connection of the CA and CK display LED. The CA pin is typically connected to positive supply while the CK connects to ground.

http://www.electronics-tutorials.ws/blog/7-segment-display-tutorial.html

[SatyamBhujan]

Thank Tou Tien_P...

This works... You are a genius 🙂

[SatyamBhujan]

Why is the "F" displayed despite no switch was closed???

[Tien_P]

THis LED is a conceptual part, it's there if you want to quickly display a 4-bit binary in decimal. If the input data is 0000 you will see a 0, and if input is 0001 you see a 1. I don't think this part is available in the real world.

In the real world, you need a binary to decimal converter chip such as 74LS47 to convert a 4-bit to decimal.  You can have a look at the following link (figure 37) to view the connection.

http://www.premiumorange.com/daniel.robert9/anglais/Digit/Digit_10TS2.html

Download the 7447 datasheet for more information.

[SatyamBhujan]

Going to try that with the 74LS47