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Basics

Signal visualization

Wires on the canvas change color depending on the signal they carry:

• Orange — active bit signal (logic 1)
• Gray — inactive signal (logic 0)
• Blue — active 8-bit bus (value > 0); dark blue — inactive (value 0)

Active wires also show flow dots — small circles moving along the line. They indicate the direction of signal propagation: from a component's output to another's input.

You can toggle input nodes (Input / Bus Input) directly on the canvas without running a test. Click the «0» circle on an input — it switches to «1», the signal instantly propagates through the entire circuit, and all wire colors update. This is great for debugging: manually flip inputs and watch how the circuit responds, without waiting for a full verification.

Error highlighting

When you press ▶ (Run Test), the circuit is checked against the truth table. If any row's expected output doesn't match the actual value:

• The wire leading to a failing output turns red with a bright glow
• The output node itself is highlighted in red with an outer ring

Error highlighting stays until you modify the circuit (add/remove a component or connection) or run the test again. When all tests pass, the highlighting clears automatically.

«Info» tab

The right panel has an «Info» tab. Select any component on the canvas — its description, category, and truth table appear in this tab. A handy reference: no need to search for documentation — all gate info is right there.

Truth table

A timing diagram is displayed above the truth table. Columns are separated by dashed lines — each clock cycle is distinct.

Hover a row in the table below — the corresponding column highlights on the diagram. Hover a column on the diagram — the corresponding row highlights in the table. This helps match expected and actual values to time intervals. Learn more about timing diagrams →

Test vectors

Each row of the truth table is a test vector: a set of input values and expected output values. When you press ▶ (Run Test), the simulator applies the inputs from the current row, propagates signals through the entire circuit, and compares actual outputs against expected values.

• Combinational levels — all vectors are checked independently: for each row the circuit resets, inputs are applied, outputs are computed. Row order does not matter.
• Sequential levels (with a clock signal) — vectors are applied sequentially, one after another, without resetting state between them. The circuit "remembers" previous steps — just like a real digital circuit with memory. Rows with the special inClock field mark a clock edge: at that moment, flip-flops and registers capture input data.
• Verilog levels — same principles, but checking runs through the Verilog simulator. For sequential designs, the waveform viewer visualizes signal history: inputs, outputs, and internal wires.

A test status appears below the table: green — all vectors passed; red — mismatches found. For failed rows, the "Exp" / "Act" columns show which bits didn't match. Click a failed row to expand a dump of all internal signals — useful for debugging.

Clock control

On levels with memory and feedback loops (10–12, 16+), a «Clock Control» panel appears in the right sidebar. Purely combinational levels (13–15) have no clock — the panel hides. In «Sandbox» mode, Clock Control is always available.

• ▶ / ⏸ — start / pause automatic clocking. The graph updates at the selected frequency.
• ⏭ — single step: advance exactly one clock tick. Great for debugging — see how state changes after each step.
• Hz — speed slider: from 1 to 100 steps per second. Higher is faster.
• Ticks — tick counter. On the CPU level (16), this is the number of executed instructions.

Step mode (⏭) helps you understand what the circuit does: one click, one tick. Automatic mode (▶) verifies that the circuit runs stably over time.

Controls

• Drag an element from the component bar onto the canvas
• Drag from an element's port — create a connection
• Delete — remove the selected element
• Mouse wheel — zoom in/out
• F9 — run circuit verification
• Ctrl+Shift+F — open search for components and theory

Search components and theory

Press Ctrl+Shift+F (Cmd+Shift+F on Mac) or click the Search button in the toolbar to open the command palette — a Spotlight-style search panel.

Start typing a component name, article title, or level — the panel instantly finds matches among:

• Components (datasheets) — NAND, Half Adder, registers, ALU, and more
• Library articles — from «Introduction to Circuit Design» to «Timing Diagrams»
• Level guides — step-by-step walkthroughs for all 40 levels

Navigate with ↑↓ arrows, press Enter to open — a component opens in the «Info» tab, an article or guide opens in a new tab.

Hints

Each level offers two hint levels. Press the button in the toolbar. The first hint shows a solution guide and warns about the transistor penalty. The second hint inserts the complete solution onto the canvas and deducts transistors from your game balance.

Modes

• Tasks — progress through levels in order with verification
• Sandbox — free experimentation with all unlocked elements

AI Tutor

The right sidebar has an «AI Tutor» tab — an AI assistant that analyzes your circuit, finds errors, and asks guiding questions in a Socratic style. 100 requests per day are available.

Shortcut buttons send common requests:

• Check circuit — find errors without giving a solution
• Explain level — rephrase the task in simple terms
• I give up — show a step-by-step solution

AI Tutor can make mistakes. Do not blindly trust it — double-check results.

Game Economy

Completing levels successfully earns you the in-game currency — Transistors (T). The currency serves as a scoring system and is not spent on anything.

• Level reward depends on difficulty: easy levels (1–5) give +50 T, medium (6–11) — +100 T, hard (12–29) — +150 T.
• Hint penalty: using the ready-made solution (2nd hint) deducts an amount equal to the reward, with a minus sign (e.g., −50 T). Your balance can go negative.
• Re-grade: if you passed a level with a penalty, then reset it and built the circuit on your own — the penalty is refunded, and the full reward is granted. The system rewards learning!

Your current balance is displayed in the top bar (next to the «Tasks» and «Sandbox» buttons). Clicking the balance opens the Engineer Profile — a table with your full completion history: which levels are done, when, how many hints used, and how many transistors earned.

Library

Detailed materials are available in the Library:

• Level Guides — step-by-step solutions for all 40 levels
• Assembler Manual — complete instruction set documentation
• Circuitry Articles — logic gates and fundamentals