Experiment 20 - RS Latch with NAND Gate

In Experiment 3 you built a RS latch with NOR gates. You can also build a RS latch with NAND gates...

Analogous to Experiment 3 you get the truth table of NAND gates with feedback. It shows differences from the truth table with NOR gates...

• R and S are not equal: Q follows S and Q' follows R.
• R and S are equal 0: the last result of Q and Q' is stored.

When R = S = 0, the result is not defined. This you can easily observe when you connect the battery and no pushbutton switch is pressed.

Circuit diagram RS latch with NAND gates.

Circuit RS latch with NAND gates. (Enlarge)

Can you get back the truth table of the RS latch with NOR gates by inverting the inputs R and S into the RS latch with NAND-Gatter...?

In the next experiment you take a look at this in more detail...