Experiment 22 - The Gated D Latch with NAND Gates

In the experiment 6 you have built a gated D latch with NOR gates. Now you build it with NAND gates and observe the difference...

Consider the circuit shown. It is the same circuit as in Experiment 6, only this time it is constructed with NAND gates...

Circuit diagram gated D latch with NAND gates.

Circuit symbol gated D latch with NAND gates.

As a result the behavior of the input E is inversed...

• With E= 0 you close the gated latch and the last result is stored.
• When E = 1, you open the gated latch and with D you can switch between the two states.

Circuit gated D latch with NAND gates. (Enlarge)

The input E of a gated D latch with NAND gates is inverted with respect to the gated latch with NOR gates...

In the next experiment, you expand the DE-flip-flop by two inputs.