T Flip flops
T flip flop or toggle flip flop avoids the indeterminate state found in the working of RS flip flop and provides only one input, hence the flip flop acts as a toggle switch.
In T flip flop extremely narrow triggers drive the T input. For example, the Q input equals 0 before the trigger and the upper AND gate is enables and the lower AND gate is disabled. After the trigger, the S input is higher.
There is one disadvantage in T flip flops i.e, the trigger is known only if the previous state is known.
Truth table for T flip flops:
| Qn | T | Qn+1 |
| 0 | 0 | 0 |
| 0 | 1 | 1 |
| 1 | 0 | 1 |
| 1 | 1 | 0 |
Excitation table for T flip flop
| T | Q |
| 0 | Qn |
| 1 | n |
Reference