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Home > Other > 74LS76 Dual JK Flip-Flop: Pinout, Uses, Datasheet and Function Details

74LS76 Dual JK Flip-Flop: Pinout, Uses, Datasheet and Function Details

tempo di aggiornamento: 2023-11-29 13:51:48


Have you ever pondered the intricacies of bit storage within the domain of digital electronics? If you have, we're here to elucidate how flip-flops, specifically the 74LS76 with its dual JK flip-flops, play a crucial role in facilitating this process. JK flip-flops find widespread application in everyday electronic devices, and while various methods exist, their fundamental function is bit storage, enabling subsequent utilization in digital electronic circuits.

The JK flip-flop, distinguished by its clock input, pre-set, and clear functionalities, stands as a popular choice. Its state transitions are contingent upon the clock pulse signal, which can manifest as either a positive or negative edge. This clock signal bestows numerous advantages upon the flip-flop, enhancing its performance. Furthermore, the 74LS76 incorporates features that mitigate or prevent the occurrence of invalid outputs. This article provides a complete guide to 74LS76 covering datasheet, 7476 ic pin configuration, features, alternatives, and applications. Everything you need to know about how to use JK Flip-Flop.

What is 74LS76?

The 74LS76 IC boasts dedicated J, K, Clock Pulse, Direct Set, and Direct Clear inputs. These dual flip-flops have been engineered such that, when the clock signal rises to a HIGH state, the inputs become active, allowing for the acceptance of data.

74LS76 IC.png

The 74LS76 IC is essentially synonymous with JK flip-flops, primarily employed for bit storage but also demonstrating utility in various other applications. Several key attributes contribute to the widespread popularity of JK flip-flops, including:

  • The clock input feature.

  • The presence of preset input pins.

Notably, JK flip-flops exhibit state transitions upon the application of a clock pulse signal, which can manifest as either a positive or negative edge. Furthermore, the 74LS76 possesses the capability to filter out invalid output conditions.

7476 IC Pin Diagram

Here is the pinout diagram of 74LS76:

74LS76 Pinout.png

74ls76 Pinout Configuration

The following is the pin description of 74LS76:

Pin No.Pin NameDescription
5VccPowers the IC typically with 5V
13GroundConnected to the ground of the system
JK Flip Flop – 1 / JK Flip Flop - 2
1,6Clock-1/ Clock-2These pins must be provided with clock pulse for the flip flop
2,7Preset-1 / Preset-2Preset input pin drives Flip Flop to a set state
16, 121K/ 2KInput pin of the Flip Flop
4,91J / 2JAnother Input pin of the Flip Flop
14, 101Q(bar) / 2Q (bar)Inverted output pin of Flip Flop
15,111Q / 2QOutput Pin of the Flip Flop
3,81 CLR (bar)/ 2 CLR (bar)Clear input pin drives Flip Flop to a reset state

74ls76 Pin Details

  • Pin 1(1 CLK): Clock input for the first JK flip-flop. A HIGH to LOW pulse influences this flip-flop.

  • Pin 2(1 PRE'): Preset input for the first flip-flop, setting 1Q to HIGH. Active LOW.

  • Pin 3(1 CLR'): Clear input for the first flip-flop, resetting its output. Active LOW.

  • Pin 4(Input 1, J): First input for the first flip-flop, receiving data (HIGH or LOW).

  • Pin 5(Vcc): Power supply pin, providing operational power to the IC.

  • Pin 6(2 CLK): Clock input for the second JK flip-flop. A HIGH to LOW pulse affects the IC.

  • Pin 7(2 PRE'): Preset input for the second flip-flop, setting 2Q to HIGH. Active LOW.

  • Pin 8(2 CLR'): Clear input for the second flip-flop, resetting its output. Active LOW.

  • Pin 9(Input 2, J): First input for the second flip-flop, receiving data (HIGH or LOW).

  • Pin 10(2Q'): Second output for the second flip-flop, providing the inverted output of Pin 11.

  • Pin 11(OUTPUT 2Q): First output for the second flip-flop, offering its output bit.

  • Pin 12(Input 2K): Second input for the second flip-flop, receiving the second data bit (HIGH or LOW).

  • Pin 13(GND): Ground pin, creating a common ground with the power supply and other devices if required.

  • Pin 14(1Q'): Second output for the first flip-flop, supplying the inverted output of Pin 15.

  • Pin 15(OUTPUT 1Q): First output for the first flip-flop, providing its output bit.

  • Pin 16(Input 1K): Second input for the first flip-flop, receiving the second data bit (HIGH or LOW).

Note: Comprehensive technical details can be available in the 74LS76 datasheet provided at the end of this page.

Features and Specifications

Below, you'll find some of the essential features and specifications of the 74LS76 JK flip-flop.


  • Dual JK Flip-Flop Package in a Single IC

  • Operating Voltage Range: 2V to 6V

  • Minimum High-Level Input Voltage: 2V

  • Maximum Low-Level Input Voltage: 0.8V

  • Minimum High-Level Output Voltage: 3.5V

  • Maximum Low-Level Output Voltage: 0.25V

  • Operating Temperature Range: -55°C to -125°C

74LS76 Dual JK Flip-Flop Characteristics:

  • The 7476A is available in various packages, including 14-pin PDIP, GDIP, and PDSO.

  • Two essential features of the 74LS76 are its functional clear and preset.

  • This IC conforms to the TTL output standard, ensuring compatibility with microcontrollers and other TTL devices.

  • The 74LS76 IC can function as a standalone flip-flop without impacting the others.

How does JK Flip-Flop Work? 

The 74LS76 is equipped with 5 input pins and 2 output pins, and its output state is influenced by almost every input pin. When the IC's reset pin is in a LOW state, the output pin assumes a LOW state, while the inverted output takes on a HIGH state. Conversely, when the preset pin is set to a HIGH state, the output pin becomes HIGH, and the inverted output becomes LOW. To maintain the IC in a stable condition, both of these pins should be kept LOW. If both pins are set to a HIGH state, both the output and inverted output will be in a HIGH state. The reset and clear pins establish distinct conditions for these inputs.


CLEARPRESETOutputInverted Output

When clear = 1 and preset = 1, the output undergoes a transition from HIGH to LOW upon the rising edge of the clock pulse, depending on the J and K inputs. If both J and K inputs are LOW, the output remains unchanged, depending on the previous state. In the case of J = 1 and K = 1, the output toggles with each clock pulse. The other states follow the truth table provided below.


H – L00QQ’
H – L0101
H – L1010

These two tables above elucidate the general operation of the JK Flip-Flop, while the following truth table outlines the functionality of the 74LS76, incorporating its clear and preset features.

74LS76 truth table.png

74LS76 truth table

0-9 Counter Example with 74LS76

In this illustration, we will construct a 3-bit counter using JK flip-flops and subsequently display the decimal equivalent on a 7-segment display. To create a three-bit counter, we will introduce an additional component, the AND gate, in addition to employing four JK flip-flops. Once the counter design is established, we will employ the 74LS76 IC to convert the binary data into a common cathode 7-segment display. The clock pulse will drive the output, and the IC will present the data on the 7-segment display. An image of this setup is provided below.


With three bits of data, we can store values ranging from 000 to 111, totaling eight different values. The 7-segment display will reveal these values in decimal form, spanning from 0 to 7. Each JK flip-flop stores and generates new values with each clock pulse. To facilitate this conversion, we employ the 74LS48 as a BCD to 7-segment decoder. Data can be read at any point before a change in the clock pulse. This feature proves valuable in microprocessors and controllers, where manual signals control the clock pins, ensuring data retention until the moment is opportune for replacement. This attribute makes the flip-flop an excellent choice for temporary data storage across multiple devices.

Proteus Simulation

Where to use 74LS76 JK Flip-Flop

The 74LS76 is a dual in-line integrated circuit (IC) comprising two JK flip-flops within a single package. Each flip-flop is capable of independent operation, making it adaptable to a variety of applications. JK flip-flops are renowned for their efficiency and can serve specific purposes in isolation.

These flip-flops, often referred to as latching devices, possess the capacity to remember and retain a single bit of data, thereby latching the output accordingly. This characteristic renders them valuable in functions such as shift registers, control registers, storage registers, or wherever a modest memory capacity is essential. When multiple flip-flops are cascaded, they can collectively function as an Electrically Erasable Programmable Read-Only Memory (EEPROM) for storing a limited amount of data. The JK flip-flop's stability across all input scenarios, as demonstrated by its truth table, enhances its practicality.

If you seek an IC suitable for latching purposes or the establishment of a compact programmable memory within your project, the 74LS76 IC presents an excellent choice.

How to use 74LS76

As mentioned previously, this IC encompasses two JK flip-flops and typically operates with a +5V power supply. The specification details the range of minimum and maximum input and output voltages for the input pins (J, K) and the output pins (Q, Q bar). To visualize the operation of the J-K flip-flop, refer to the image below.


The asynchronous active-low inputs for preset and clear play a pivotal role. When preset and clear are set to a low state, they take precedence over the clock and J-K inputs, compelling the output to adopt the steady-state levels detailed in the truth table provided below.

74LS76 Equivalent

74LS73, MC74HC73A, and SN7476 can be equivalent to 74LS76. Additionally, 74LS107 and 4027B serve as alternative JK flip-flops to 74LS76.

74LS76 Applications

  • Shift registers

  • Memory and control registers

  • EEPROM circuits

  • Latching devices

  • Suitable for counter-design

74LS76 2D Model Diagram


74LS76 Datasheet

Download 74LS76 Datasheet PDF.


The 74LS76 Dual JK Flip-Flop is a fundamental building block in the world of digital electronics. By understanding its pin configuration, applications, and function details, you can harness its capabilities to design and implement intricate digital circuits.

Read More

Precedente: 4-Bit Binary Counter: Working, Circuit Diagram & Applications

Prossimo: The Ultimate Guide to Implementing NOR Gate from NAND Gate


  • How does 74LS76 work?
  • The 74LS76 dual flip-flop has been engineered such that when the clock signal goes to a HIGH state, it activates the inputs, allowing for the acceptance of data. The behavior of the J and K inputs adheres to the Truth Table, provided that minimum set-up times are adhered to.

  • What is the J-K flip-flop?
  • The JK Flip-Flop can be described as an SR flip-flop with a gating mechanism, featuring an integrated clock input circuitry. This design serves to mitigate the occurrence of illegal or invalid output conditions that may arise when both inputs, S and R, are set to a logic level of "1."

  • What is the IC number of 74LS76?
  • 7476.

  • What is the theory of IC 7476?
  • The IC 7476 represents a dual JK master-slave flip-flop, featuring preset and clear inputs. When the inputs J and K differ, the output Q assumes the value of J at the following clock edge. If both J and K are in the low state, no alteration takes place. However, if both J and K are set to a high state at the clock edge, the output toggles between two distinct states.

  • What is the difference between 74LS76 and 7476?
  • The 7476 IC is a master-slave J-K flip-flop, whereas the 74LS76 is a J-K flip-flop triggered on the negative edge. Notably, both chips share an identical pin configuration. They feature synchronous inputs for J, K, and Cp, as well as asynchronous inputs.

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