# T Type Flip Flop

T Type Flip Flopis another type of bistable sequential logic circuit based on the previous clocked JK flip flop circuit. T Type Flip Flop can be used as a basic digital element or as a counter to store bit information. The T-type Flip Flop has a single input that changes the status on the positive edge (rising edge) or negative edge (falling edge) of an input clock signal or pulse. It also has one or two complementary Q and Q' outputs.

Type T Flip Flop is not commercially available as a custom TTL or CMOS logic chip. It can be easily created by connecting the J and k entries of a basic JK flip flop, where the J input behaves like a Set (s) command and the K input acts as a Reset (R) command. From our previous post, we remember that the input status (high or low) of the JK flip flop and its current stable state is an asynchronous flip flop, in which it determines the next switching state.
In general, the JK Flip flop can be classified as a "universal" flip flop.

## Basic JK Flip Flop Circuit with NAND Doors

The circuit above shows the basic configuration of a JK flip-flop using four NAND doors, but they can also be built using NOR doors. The JK flip-flop has three entries labeled J, K and watch (CLK). If both J and K inputs are low (J = K = 0), there will be no change in Q, regardless of the number of times the clock pulse is applied.

### Properties Table for JK Function

Here: What X means is irrelevant. _← The meaning will be the positively rising edge of the clock pulse.

We can then define this switching action in the Boolean form as follows:

Here: Q represents the current stable state of flip flop. Q + 1 is the next switching state.

## T Type Flip Flop

Although the data (D) is a variation of a clocked SR flip flop created using flip-flop, NAND or NOR gates, the T-type Flip Flop is a variation of the clocked JK flip-flop. The Toggle or T-type flip-flop takes its name from the reversal of two Q and Q outputs from their previous state each time it is triggered. That is, the outputs Q and Q change from "0" to "1" and previously "1" to "0".

JK Flip-Flops are renamed T for Toggle flip-flop. It is usually represented by the logic or graphic symbol shown. The Toggle schema symbol has two entries. One represents the "toggle" (T) entry and the other represents the "clock" (CLK) entry.

The chevron triangle at the entrance to both T-type Flip Flop indicates that it is a device with edge triggering. If there is a small bubble or circle at the entrance, it indicates that the flip flop switches from the negatively falling edge (high to low) of each pulse. Otherwise, each input pulse changes the status on the positive or rising trading edge (low to high).

Next, we can create the logic circuit of a single bit transition flip flop using the basic JK flip flop by connecting the J and K data entries. Here, the commonality in the connection of the two entries is T, as shown.

### T Type Flip Flop

Initially, suppose clk and input T are both low (CLK = T = 0) and output Q is high (Q = 1). On the rising edge or falling edge of a CLK pulse, the logic "0" condition in T prevents the output in Q from changing the situation. Thus, the output remains unchanged when t = 0 is.

Now suppose the t input is high (T = 1) and clk low (CLK = 0). On the rising edge of a CLK pulse at T1 time (assuming positive transition), the output status in Q changes and is low. This makes Q high. In the negative transition of the clock pulse from high to low at T2 time, the flip flop has no effect on Q output as it resets to a single stable state.

At the next rising edge of the clock signal at T3 time, the logic "1" in the T switches to Q and changes its status, making Q output high again. The negative transition of the clk pulse from high to low at T4 time once again has no effect on the output. Thus, the Q output of the flip-flop is "snapped" on each positive departure edge of the CLK pulse (for this example).