Free online digital logic simulator: gates, flip-flops and counters

Build digital circuits free in your browser: logic gates, flip-flops, counters, MUX, 74HC chips and a logic analyzer, with 28 auto-checked DSD builds.

Build circuits from logic gates with 2 to 8 inputs, multiplexers, decoders, D, T, JK and SR flip-flops, counters, shift registers and 74HC chips, drive them with switches and a clock, and read the result on LEDs, 7-segment displays and a logic analyzer. No code and no sign-in.

28 guided digital-logic builds, checked automatically against their truth tables · K-Map Lab · Embedded Lab (Arduino, ESP32, Pico)