The CD4027 is a frequently employed JK flip-flop designed for data retention purposes. This integrated circuit (IC) comprises two identical or equivalent JK flip-flops. Each set of JK flip-flops within the IC is equipped with pins labeled J, K, Set, Reset, Clock, and two output terminals that exhibit complementary behavior. The JK flip-flop finds applications in various scenarios, including voice registers, counters, and control circuits.
JK Flip Flop with CD4027 Circuit Diagram:
Circuit Components:
- IC
- CD4027
- Resistor
- R1(1K)
- R2(470E)
- R3(10K)
- C1(2.2uf)
- S1
- LED
- D1(1N4148)
JK Flip Flop with CD4027 Circuit Description:
The CD4027 serves as a master-slave JK flip-flop primarily utilized in toggle mode. This integrated circuit (IC) facilitates signal alteration by receiving control input from one or more input terminals and producing output at one or more output terminals. The output value is not solely dependent on the present input state but also on the current output state, which in turn relies on the previous state. Flip-flops have historically played a crucial role in computer memory circuitry.
Within a JK flip-flop, there exist four input pins, namely J and K, set and reset pins, and output pins labeled Q and Q. The values at Q and Q are always in opposition, meaning that when Q is high, Q is low, and the outcome at both terminals is dictated by the input configuration. The pin arrangement of the IC is illustrated in the diagram below.
The flip-flop’s state is under the influence of the logic levels present at the input terminals J and K, in addition to internal control. With every successive clock cycle, the state undergoes a change. Contrarily, the set and reset pins remain unaffected by the clock pulse and activate when a high signal is applied to either of the input terminals.
The circuit in question triggers its operation at the leading edge of the switching pulse, which corresponds to the moment the switch is pressed, leading to an alteration in the output state. As evidenced in the circuit, both input terminals J and K are set to a high value. Consequently, the clock pulse oscillates between high and low states during each positive or negative transition. This particular flip-flop condition is commonly referred to as the “forbidden state,” and it can be validated using the truth table presented below.
Upon pressing the switch, a short-lived clock pulse is dispatched to the IC’s input, leading to a high output at pin 1. This high output state persists until the arrival of the second pulse. The output becomes active when it is linked to a load or an LED. Upon the arrival of the second clock pulse at pin 3, the IC’s output transitions to a low state, causing the LED or connected load to deactivate.
The functionality of this circuit hinges on the switch being pressed, but it can be easily disrupted by interchanging the positions of the switch and resistor.
