LAB NO.03

Objective:

To verify truth table of 74160 (CTR Div 10) and 74190 (CTR Div 10) Decade counter.

Equipment:

1 Logic probe

1 Proto board

1 Set of wires

1-74160 IC

1 74190 IC

Theory:

A decade counter is a binary counter that is designed to count to 1010, or 10102. An ordinary four-stage counter can be easily modified to a decade counter by adding a NAND gate as shown in figure 3-25. Notice that FF2 and FF4 provide the inputs to the NAND gate. The NAND gate outputs are connected to the CLR input of each of the FFs.

74160 (CTR Div 10):

There are two modes in 74160 counter & load, if load is enable then ic will output simply the input bits, if counter is active ic will count from 0-9 and RCO will give active high only at 9th count otherwise give low output.

74190(CTR Div 10):

There are two modes in 74190 load and up\/down count. if load is enable then counter stops and input data is simply output. if counter is enable the MAX/MIN pin gives output at 9 and 0 and RCO pin becomes active low at these two output.

Circuit Layout:

74160 (CTR Div 10):

74190(CTR Div 10):

Pin Layout:

74160 (CTR Div 10):

74190(CTR Div 10):

Observations:

Truth Table for 74160 Decade Counter

Clock pulse / up / Q4 / Q3 / Q2 / Q1 / down
0 / ↑ / ↓
1 / ↑ / ↓
2 / ↑ / ↓
3 / ↑ / ↓
4 / ↑ / ↓
5 / ↑ / ↓
6 / ↑ / ↓
7 / ↑ / ↓
8 / ↑ / ↓
9 / ↑ / ↓
Clock pulse / up / Q4 / Q3 / Q2 / Q1 / down
0 / ↑ / ↓
1 / ↑ / ↓
2 / ↑ / ↓
3 / ↑ / ↓
4 / ↑ / ↓
5 / ↑ / ↓
6 / ↑ / ↓
7 / ↑ / ↓
8 / ↑ / ↓
9 / ↑ / ↓
4 / ↑ / ↓
5 / ↑ / ↓
6 / ↑ / ↓
7 / ↑ / ↓
8 / ↑ / ↓
9 / ↑ / ↓

Conclusion:

  • It will count from 0 to 9 and produce RCO high at 9th count in 74160 decade counter.
  • It will show 1 at o and 9 state else all will be 0 on others state in 74190 decade counter.

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