Summary
1.A flip flop can remain in its last state until an external trigger forces it to the other state because of this, it is a memory element
2.In the inactive state a flip flop stores or remembers because it remain in its last state.
3.An invalid condition exits when both R and S are high in an RS Flip flop. this undesirable state is forbidden because it represents a contradiction
4.one way to build an RS flip flop is with cross coupled NOR gates. Alternatively,
NAND gates can be used
5.Usually, a signal called the clock determines when a flip flop can change states.
6.By including an inverter, we can covert an RS flip flop into a D flip flop. the big advantage of the D flip flop is the lack of an invalid condition
7.A positive edge triggered D flip flop stores the data bit only on the rising edge of the clock.
8.Preset and clear alow a direct set or direct reset of flip flop regardless of what the cock is doing
9.A toggle flip flop changes state with each clock cycle and is known as a divide by 2 flip flop
10. Depending on the values of J and K, a JK flip flop will either do nothing, set reset or toggle