TAMS / Java / Hades / applets (print version): contents | previous | nextTTL-series counters (7490,7492,7493)
DescriptionThis applet demonstrates the 749x counters
from the TTL-series or HC-series of (small-scale) integrated circuits.
The most popular counter ICs from the 74xx series are the following,
each of which is included in the applet:
- 7490, a 1:10 counter which can be split into 1:2 and 1:5
- 7492, a 1:12 counter which can be split into 1:2 and 1:6
- 7493, a 1:16 counter which can be split into 1:2 and 1:8
All three ICs are based on JK flipflops and feature asynchronous
reset inputs.
The first counter stage uses separate input and output pins,
and can be used as a standalone 1:2 counter stage.
The remaing three stages are connected internally, so that the
carry and feedback paths are not accessible from the outside.
To connect both stages, the A output of the first stage
is connected to the CB input of the next stage(s).
Note the curious 0-1-2-3-4-5-8-9-a-b-c-d count-sequence of the 7492.
Exercise:
Describe how to realize the missing counters (e.g., 1:3, 1:7, 1:9)
with the 749x integrated circuits.
Run the applet | Run the editor (via Webstart)
Impressum | 24.11.06
http://tams.informatik.uni-hamburg.de/applets/hades/webdemos/30-counters/60-ttl/749x_print.html
