Types of Flip-Flop Circuits in Digital electronics

Types of Flip-Flop Circuits

Types of flip-flops:

1. RS Flip Flop
2. JK Flip Flop
3. D Flip Flop
4. T Flip Flop

Flip flop v/s Latch

The basic difference between a latch and a flip-flop is a gating or clocking mechanism.

Read the full comparison of Flip Flop v/s latch here

For example, let us talk about SR latch and SR flip-flops. In this circuit when you Set S as active the output Q would be high and Q’ will be low. This is irrespective of anything else. (This is an active-low circuit so active here means low, but for an active high circuit active would mean high)

 flip flop, on the other hand, is synchronous and is also known as gated or clocked SR latch.

SR Flip-Flop

• SR flip-flop: Is similar to an SR latch. Besides the CLOCK input, an SR flip-flop has two inputs, labeled SET and RESET. If the SET input is HIGH when the clock is triggered, the Q output goes HIGH. If the RESET input is HIGH when the clock is triggered, the Q output goes LOW.
  Note that in an SR flip-flop, the SET and RESET inputs shouldn’t both be HIGH when the clock is triggered. This is considered an invalid input condition, and the resulting output isn’t predictable if this condition occurs.
• D flip-flop: Has just one input in addition to the CLOCK input. This input is called the DATA input. When the clock is triggered, the Q output is matched to the DATA input. Thus, if the DATA input is HIGH, the Q output goes HIGH, and if the DATA input is LOW, the Q output goes LOW.
  Most D-type flip-flops also include S and R inputs that let you set or reset the flip-flop. Note that the S and R inputs in a D flip-flop ignore the CLOCK input. Thus, if you apply a HIGH to either S or R, the flip-flop will be set or reset immediately, without waiting for a clock pulse.
• JK flip-flop: A common variation of the SR flip-flop. A JK flip-flop has two inputs, labeled J and K. The J input corresponds to the SET input in an SR flip-flop, and the K input corresponds to the RESET input.
  • The difference between a JK flip-flop and an SR flip-flop is that in a JK flip-flop, both inputs can be HIGH. When both the J and K inputs are HIGH, the Q output is toggled, which means that the output alternates between HIGH and LOW.
    For example, if the Q output is HIGH when the clock is triggered and J and K are both HIGH, the Q output is set to LOW. If the clock is triggered again while J and K both remain HIGH, the Q output is set to HIGH again, and so forth, with the Q output alternating from HIGH to LOW at every clock tick.
  • T flip-flop: This is simply a JK flip-flop whose output alternates between HIGH and LOW with each clock pulse. Toggles are widely used in logic circuits because they can be combined to form counting circuits that count the number of clock pulses received.
    You can create a T flip-flop from a D flip-flop by connecting the Q-bar output directly to the D input. Thus, whenever a clock pulse is received, the current state of the Q output is inverted (that’s what the Q-bar output is) and fed back into the D input. This causes the output to alternate between HIGH and LOW.
    You can also create a T flip-flop from a JK flip-flop simply by hard-wiring both the J and K inputs to HIGH. When both J and K are HIGH, the JK flip-flop acts as a toggle.
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