Consider the circuit diagram containing two NOR gates. You realize it has two outputs Q and Q', which can take two states...
![]() Circuit diagram bistable multivibrator. |
Possible states of Q and Q'. |
A bistable multivibrator switches back and forth between the two states (hence the part bi-). Has the multivibrator found a result, it remains stable. Only by using the inputs R and S you switch the multivibrator. This behaviour applies to all latches and flip-flops.
![]() Circuit bistable multivibrator. (Enlarge) |
With the circuit shown, it becomes more evident how it works... When you connect the battery, either Q or Q' lights up. This is determined by chance. After that you can switch between the two results by using R and S. Try this out to understand its behaviour. This is already the first latch you built. |