3-bit ripple counter: build and simulate it online
Each T flip-flop toggles when the one before it falls: the count ripples up the chain.
Build the 3-bit ripple counter in the free online simulator — it checks your circuit automatically.
What you need
- 1 logic switches labelled CLK
- 3 probes labelled Q0, Q1, Q2
- 3 T (or JK) flip-flops
Step by step
- Inputs and outputs. From the Logic section of the library, drop digital inputs (0/1 boxes) or logic switches for the inputs, and digital outputs or probes for the outputs; give each its label in the inspector (the checker finds them by label). Switch CLK; Probes Q0, Q1, Q2
- Three T flip-flops. Tie every T to a Logic 1. CLK clocks the first; each QN clocks the next (a rising QN is a falling Q).
- Prove it. Eight clocks: 1, 2, … 7, 0.
Expected sequence
| # | inputs | clock | Q0 | Q1 | Q2 |
|---|---|---|---|---|---|
| 1 | — | ↑ | 1 | 0 | 0 |
| 2 | — | ↑ | 0 | 1 | 0 |
| 3 | — | ↑ | 1 | 1 | 0 |
| 4 | — | ↑ | 0 | 0 | 1 |
| 5 | — | ↑ | 1 | 0 | 1 |
| 6 | — | ↑ | 0 | 1 | 1 |
| 7 | — | ↑ | 1 | 1 | 1 |
| 8 | — | ↑ | 0 | 0 | 0 |
Frequently asked questions
How do you build a 3-bit ripple counter?
Each T flip-flop toggles when the one before it falls: the count ripples up the chain. In short: inputs and outputs, then three t flip-flops, then prove it.
How does a 3-bit ripple counter behave clock by clock?
It is checked over 8 steps: count 1, count 2, count 3, count 4, …. The table on this page shows the expected Q0, Q1, Q2 after each clock.
What parts do you need for a 3-bit ripple counter?
3 T (or JK) flip-flops — plus logic switches for the inputs and probes for the outputs.
Can I simulate a 3-bit ripple counter online for free?
Yes. Open it in the BitForBytes Embedded Lab, a free browser-based circuit and logic simulator: drag in the gates, wire them, and press "Check my circuit" — every clock cycle is simulated and marked for you. No download or sign-up needed.
Part of DSD 35 · Ripple counters in the free BitForBytes digital system design course.