JK Flip-Flop Behavior with J=1, K=1
For a positive-edge-triggered JK flip-flop, the behavior is determined by the inputs J and K when the clock signal transitions from low to high (rising edge).
When both the J and K inputs are high (logic 1):
- J = 1
- K = 1
In this specific state (J=1, K=1), the JK flip-flop is designed to change its output state to the opposite of its current state. This action is known as toggling.
If the current output (Q) is 0, it becomes 1. If the current output (Q) is 1, it becomes 0.
JK Flip-Flop Characteristic Table
The characteristic table summarizes the next state (Qnext) based on the current state (Q) and the inputs (J, K) upon the clock edge:
| J | K | Qnext | Description |
|---|---|---|---|
| 0 | 0 | Q | No Change |
| 0 | 1 | 0 | Reset |
| 1 | 0 | 1 | Set |
| 1 | 1 | Q' | Toggle |
As shown in the table, when J=1 and K=1, the next state Qnext is the complement of the current state Q (denoted as Q'). This confirms that the output will toggle on the rising edge of the clock.
Important Questions from Flip Flops and Counters
Race around condition can be removed by using the combination of:
A JK flip flop with J = K = 1 has a 100 kHz clock input. The Q output is
A ring counter with 5 flip-flops will have:
A 4 bit counter is used to count form 0, 1, 2 …. n. Value of ‘n’ is
Counter design can be implemented by:
