T Flip Flop

Flip-flop is a term that comes under digital electronics, and it is an electronic component that is used to store one single bit of information.

Diagrammatic Representation of Flip Flop

• Since Flip Flop is a sequential circuit its input is based upon two parameters, one is the current input and the other is the output from the previous state.
• It has two outputs, both are complements of each other.
• It may be in one of two stable states, either 0 or 1.

Basic diagram of Flip Flop

What is T Flip Flop?

• T flip flop or to be precise is known as Toggle Flip Flop because it can able to toggle its output depending upon on the input.
• T here stands for Toggle.
• Toggle basically indicates that the bit will be flipped i.e., either from 1 to 0 or from 0 to 1.
• Here, a clock pulse is supplied to operate this flop, hence it is a clocked flip-flop.

Construction of T Flip Flop

We can construct T flip in three ways namely: 

• By using SR Flip Flops.
• By using D Flip Flops.
• By using JK Flip Flops

Ways to Construct T Flip Flop

Let’s see the construction of T Flip Flop using SR Flip Flops, which require 2 AND gates and 2 NOR gates as shown below:

 

Basic Block Diagram of T Flip Flop
 

 

Here block diagram contains Toggle and clock inputs, Q and Q’ is the complemented inputs.

Working of T Flip Flop
 

Case 1: Let’s say, T = 0 and clock pulse is high i.e, 1, then output of both, AND gate 1, AND gate 2 will be 0, gate 3 output will be Q and similarly gate 4 output will be Q’ so both the values of Q and Q’ are same as their previous value, which means Hold state.
 

Case 2: Let’s say, T=1, then output of both AND gate 1 will be (T * clock * Q), and since T and clock both are 1, then the output of AND gate 1 will be Q, and similarly output of AND gate 2 will be (T * clock * Q’) i.e, Q’. Now, gate 3 output will be (Q’+Q)’ and let’s say Q’ is zero, then gate 3 output will be (0+Q)’ which means Q’ and similarly gate 4 output will be (Q+Q’)’ and since Q’ is zero, so gate 4 output will be Q’ which means 0 as Q’ is zero. Hence in this case we can say that the output toggles, because T=1.

 

Truth Table of T Flip Flop
 

• Here, T is the Toggle input, Q is present state input, Qt+1 is the next state output.
• From here we can see that, whenever Toggle (T) is 0, next state output (Qt+1) is same as current state input (Q).
• Whenever Toggle (T) is 1, next state output (Qt+1) will be complement of current state input (Q) which means it gets toggled.

Characteristic Equation

• The characteristic equation tells us about what will be the next state of flip flop in terms of present state.
• In order to get the characteristic equation, K-Map is constructed which will be shown as below:
   

• If we solve the above K-Map then the characteristic equation will be Q(n+1) = TQn’ + T’Qn = T XOR Qn

Excitation Table

Excitation Table basically tells about the excitation which is required by flip flop to go from current state to next state.
 

• Here, whenever T is 0, Qt+1 is same as input Q.
• And, whenever T is 1, Qt+1 is compliment of input Q.

Applications of T Flip Flop

There are numerous applications of T Flip Flop in Digital System, which are listed below:

• Counters: T Flip Flops used in counters. Counters counts the number of events that occurs in a digital system.
• Data Storage: T Flip Flops used to create memory which are used to store data, when the power is turned off.
• Synchronous logic circuits: T flip-flops can be used to implement synchronous logic circuits, which are circuits that perform operations on binary data based on a clock signal. By synchronizing the logic circuit’s operations to the clock signal using T flip-flops, the circuit’s behavior can be made predictable and reliable.
• Frequency division: It is used to divide the frequency of a clock signal by 2. Flip-flop will toggle its output every time the clock signal transitions from high to low or low to high, hence dividing the clock frequency by 2.
• Shift registers: T flip-flops can be used in shift registers which are used to shift binary data in one direction.

Conclusion

In this article we start from the basics of flip flops, that what actually are flip flops and then we discussed about the T Flip Flops, three two ways in which we can construct T Flip Flops, it’s Basic Block Diagram, Working of T Flip Flop, it’s Truth table, Characteristic equation as well as Excitation table and in the end we discussed the Applications of T Flip Flops.