Go from lab question to a verified circuit

No guessing, no hand-drawn netlists, no wrong answers in green. Type the question, get the file.

Download for Windows ↗ See solved questions

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Design loop idle

waiting for a question

Truth table not yet

EN	A1	A0	Y0	Y1	Y2	Y3
0	0	0	0	0	0	0
0	0	1	0	0	0	0
0	1	0	0	0	0	0
0	1	1	0	0	0	0
1	0	0	1	0	0	0
1	0	1	0	1	0	0
1	1	0	0	0	1	0
1	1	1	0	0	0	1

How Ohmwork works

Four steps. Three of them are automatic. The second one is the one worth reading.

Plain English. Paste the question exactly as the lab manual wrote it.

Y0 = EN & ~A1 & ~A0
Y1 = EN & ~A1 & A0
Y2 = EN & A1 & ~A0
Y3 = EN & A1 & A0

Step 1 of every answer: check this is what your question meant. Enable read as active-high.

attempt 1: pin G2.in2 appears in two nets

attempt 2: emitted, handed to Logisim Evolution

8 of 8 rows match

attempt 1attempt 2 · verified

.circ

decoder.circ

the exact file Logisim evaluated

Download

Built so a wrong answer is harder than no answer

Everything below is something the app actually does, not a promise.

Verified

Every row, checked by an outside tool

Digital answers are evaluated exhaustively by Logisim Evolution running the actual emitted file. Not our code checking our code.

Refused

Refuses instead of bluffing

Sequential logic, unmeasured parts, analog without LTspice: refused, with the reason named.

Not a digital questionIt names LTspice, a rectifier, 470 uF and a Zener. Use the analog path. No model was asked.

Measured

Analog too, with the honest word

LTspice checks the design against the question's own figures. A smaller promise, so it is never called "verified".

8.855V

target 9 V ± 5% · zener in breakdown · BJT active

Wrong designs die in private

A circuit the simulator disagrees with is thrown away and redone. You see the rejected attempts, not just the winner.

1234 · met the intent

Your key. Your machine.

Bring a free model key. It's stored encrypted on your laptop and never uploaded by Ohmwork.

••••••••••••••••••🔒︎

Chips are measured, not remembered

Name a 7447 and Ohmwork probes a real one in the evaluator first, all 128 input rows, then checks your design against that. Nobody's memory of a datasheet is involved.

Built on one rule

The model never grades its own work.

01 A simulator decides 02 Weaker claims look weaker 03 The one check that's yours

model designs→attempt 1→attempt 2→Logisim agrees

Nothing reaches you unless an outside tool agreed

The model writes the circuit. Logisim Evolution or LTspice runs the emitted file. If the tool disagrees, the design is thrown away and the tool's objection goes back to the model. If nothing passes, you get an honest failure.

Verified

Digital · every row

8 / 8 rows

Measured

Analog · stated figures

8.855 V

Failed

No design passed

honest

Four outcomes, four looks, never confused

An exhaustive truth-table check and a few measured numbers are different sizes of promise. The app refuses to let them look alike. Refusals and failures are their own thing too.

Step 1 · check the reading

enableactive-high

outputsY0 .. Y3, one-hot

inputsA1, A0

✓ Is this what your question meant?

The simulator can't read your question. You can.

A simulator proves the circuit matches the reading. It can't prove the reading matches the question: an enable read as active-low when the manual meant active-high passes every check. So the reading is printed first, every time.