4-Bit Binary Counter

Build a 4-bit counter and display its output in binary with LEDs.

Overview

Watch binary counting in action! Build a counter that cycles through 0-15, displaying each number in binary on LEDs.

Components Needed

  • 1x 74HC393 Dual 4-bit Counter IC
  • 1x 555 Timer IC
  • 4x LEDs
  • 4x 330Ω resistors
  • 2x Capacitors (for 555)
  • 2x Resistors (for 555)
  • 1x 5V power supply
  • 1x Breadboard

Instructions

  1. Build the Clock

    Set up a 555 timer in astable mode to generate a slow clock (about 1 Hz). This will advance the counter one step per second.

  2. Connect the Counter

    The 74HC393 has two 4-bit counters. Connect clock to 1CLK, reset to ground. Outputs Q0-Q3 give the 4-bit count.

  3. Add LED Display

    Connect LEDs with current-limiting resistors to each output. Q0 is the least significant bit (rightmost), Q3 is most significant.

  4. Test and Observe

    Power up and watch the LEDs count in binary: 0000, 0001, 0010, 0011... all the way to 1111 (15), then back to 0000.

Challenges

  • Add a 7-segment display decoder to show decimal numbers
  • Create a count-down counter
  • Build a stopwatch or timer