Hades logoHades applet banner
TTL-series 7449 seven-segment display decoder

applet icon

The image above shows a thumbnail of the interactive Java applet embedded into this page. Unfortunately, your browser is not Java-aware or Java is disabled in the browser preferences. To start the applet, please enable Java and reload this page. (You might have to restart the browser.)

Circuit Description

This applet shows a BCD to seven segment decoder realized with the TTL-series 7449 type circuit. It converts a 4-bit binary-coded decimal value, that is the numbers 0 to 9 coded as binary patterns 0000 to 1001, into the code required to drive a seven-segment display. The additional 'ndark' input allows to disable all outputs.

For input values between 10 to 15, the 7449-type circuit generates seemingly 'random' output values. Obviously, a simple circuit implementation was more important to the designers than showing useful output patterns (like letters 'A' to 'F'); You might compare these output values with the values generated by the seven-segment decoder demonstrated in the previous applet.

Print version | Run this demo in the Hades editor (via Java WebStart)
Usage | FAQ | About | License | Feedback | Tutorial (PDF) | Referenzkarte (PDF, in German)
Impressum http://tams.informatik.uni-hamburg.de/applets/hades/webdemos/10-gates/20-sevensegment/SN7449-demo.html