DLD: Logic Design & Circuits

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About this app

DLD is a digital logic design and circuits workbench for your phone. Drop gates onto the
bench, wire them together, flip a switch, and watch the signal travel through
the circuit in real time.

Built for students working through a digital logic design course — and for
anyone who wants to see Boolean algebra actually do something.

BUILD ANYTHING
• 28 components: switches, clocks, Vcc and ground, every standard gate,
tri-state buffers, multiplexers, flip-flops, displays and probes
• Gates take 2 to 8 inputs — one wide NAND instead of three cascaded ones
• Tap a component to reach its settings: input count, clock speed, colour
• A work bench far bigger than the screen, with pan, zoom and fit-to-circuit

SEE IT WORKING
• Current animates along every live wire, so you can follow a signal
• LEDs, LED bars, 7-segment and hex displays light up as the circuit runs
• A school bell that rings for as long as it has current
• Logic probes read out 1 or 0 anywhere you wire one

UNDERSTAND IT
• Boolean equations written out from whatever you have drawn
• A full truth table generated from your circuit, ready to copy out
• Conflicting drivers on a net are flagged rather than quietly wrong
• A tutorial section covering every gate symbol and its truth table

KEEP YOUR WORK
• Save and reopen as many circuits as you like
• Undo and redo everything
• Recolour wires, lamps and blocks however you want to read them

COMPONENTS
Switch · Clock · Vcc · GND · AND · OR · NOT · NAND · NOR · XOR · XNOR ·
Buffer · Tri-state buffer · Tri-state NOT · MUX · DEMUX · D flip-flop ·
T flip-flop · JK flip-flop · Virtual links · LED · LED bar · 7-segment ·
Hex display · Bell · Probe · Label

PRIVATE BY DEFAULT
No account. No sign-in. No analytics. No ads. Nothing leaves your device —
your circuits are saved on the phone and nowhere else. The app works with no
network connection at all.
Design digital logic circuits, wire them up and watch the signal run.
Updated on
Sep 22, 2026
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Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
  • No data shared with third parties
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What’s new

The app now opens on the light theme, with a switch on the front page if you
prefer the dark bench. Your choice is remembered.

Also in this release:
• The front page and the work bench both follow the theme properly
• The selection highlight reads clearly on either background