Components / Wiring
Output Pin / Probe in Logisim
Read-only signal monitor that displays the live 4-state logic value (0, 1, Z, or E) of any wire or multi-bit bus.
| Library | Wiring |
|---|---|
| Type name | Probe |
| Pins and defaults | in0, width 1..32, facing west |
How the Output Pin / Probe Works in Logisim
A Probe (or Output Pin) attaches to any wire or bus to show its live logic state without driving or loading the net. Because its single pin is purely an input, adding a Probe never causes a bus conflict or alters simulation timing.
For a 1-bit wire, the Probe displays 0, 1, Z (high-impedance floating), or E (error / short-circuit conflict). On multi-bit buses (width 2 to 32), it formats the bus bits so you can read intermediate values inside adders, multiplexers, and counters at a glance.
When debugging a broken circuit, drop Probes on intermediate nets between stages or click any Probe and use the AI Circuit Coach "Why is this 0 / 1 / E / Z?" button to trace the exact upstream gates responsible for that reading.
Tip: Place a Probe on any wire and click "Why?" in the AI Coach drawer to trace every upstream driver behind its current value.
Output Pin / Probe Pins & Pinout
| Pin | Direction | Width | Location & Role |
|---|---|---|---|
| in0 (In) | Input | 1–32 bits | Located at (0, 0), facing west by default. Connects to the wire or bus you want to inspect. |
Output Pin / Probe Truth Table & Behavior
| Displayed Symbol | Wire Color | Meaning in Logisim |
|---|---|---|
| 0 | Dark green | Logic Low (driven to 0) |
| 1 | Bright green | Logic High (driven to 1) |
| Z | Blue | Floating / high impedance (no active driver on the net) |
| E | Red (dashed) | Error / short-circuit conflict (competing 0 and 1 drivers, or invalid upstream input) |