How many flip-flops circuits are needed for a 4 bit counter?
Four
Flip-Flops for 4-Bit Counter Explained
Understanding how digital counters work involves knowing their basic building blocks. A counter is a type of sequential logic circuit that counts events or pulses, typically transitioning through a predetermined sequence of states.
Understanding Counters and Bits
A 4-bit counter is designed to count up to $2^4 = 16$ different states (from 0000 to 1111 in binary). Each state represents a specific count value.
The Role of Flip-Flops in Counters
- Flip-flops are fundamental memory elements in digital electronics.
- They are bistable multivibrators, meaning they can exist in one of two stable states, typically representing 0 or 1.
- Counters use flip-flops to store the current count value (the state).
- Each flip-flop can store one bit of information.
Determining Flip-Flops for a 4-Bit Counter
To represent a number with multiple bits, you need a separate storage element for each bit. Since a 4-bit counter needs to store a 4-bit binary number, it requires:
- One flip-flop for the least significant bit (LSB).
- One flip-flop for the second bit.
- One flip-flop for the third bit.
- One flip-flop for the most significant bit (MSB).
Therefore, for a 4-bit counter, you need exactly four flip-flops. Each flip-flop stores one bit of the count. For example, a count of '1011' (binary for 11) would be stored in four flip-flops, each holding one of the bits.
Important Questions from Counter
Which of the following is not capable of storing binary data?
A _________ is a register capable of counting the number of clock pulses arriving at its clock input.
A MOD 2 and a MOD 5 up-counter when cascaded together results in a MOD ______ counter. (in integer)
A counter is constructed with three D flip-flops. The input-output pairs are named (D0, Q0), (D1, Q1), and (D2, Q2), where the subscript 0 denotes the least significant bit. The output sequence is desired to be the Gray-code sequence 000, 001, 011, 010, 110, 111, 101, and 100, repeating periodically. Note that the bits are listed in the Q2 Q1 Q0 format. The combinational logic expression for D1 is
A 16-bit synchronous binary up-counter is clocked with a frequency fCLK. The two most significant bits are OR-ed together to form an output Y. Measurements show that Y is periodic, and the duration for which Y remains high in each period is 24 ms. The clock frequency fCLK is ______ MHz. (Round off 2 decimal places.)
