flipflop - How do I build a 4-bit synchronous direct counter using only D Flip-Flops? - Electrical Engineering Stack Exchange
How to design a synchronous counter 4 bit using JK flip flop that can count up even numbers from 0 to 14, and count down odd numbers from 15 to 0 in 1 system - Quora
Asynchronous Counter - ElectronicsHub
CircuitVerse - MOD-15 Counter
What is the circuit diagram of a Mod-15 asynchronous down counter? - Quora
A 15-bit flipflop counter (long version) - YouTube
In the digital circuit shown in figure the flip flops have set time of 5 ns and a worst case delay of 15 ns. The AND gate has a delay of 5
D Flip flop 0 15 counter - YouTube
digital logic - Realisation of asynchronous decade counter - Electrical Engineering Stack Exchange
How to design a synchronous counter using D-type flip-flops for getting the following sequence, 0-3-6-9-12-15-0 - Quora