A multimeter simulator with every position on the dial
Mokxi is a free online multimeter simulator that runs in your browser, with nothing to install and no account needed. A breadboard with no power on it: a red LED, a 1 µF capacitor, a 4.7 k and a 10 k resistor in parallel, a wire link, and one digital meter. Turn the dial and move the leads to read the diode, ohms, capacitance and continuity positions, the ones that only mean anything with the supply off.
- 455parts on the bench
- 43boards running now
- 1.00xreal time, on every board
What you can do here
In the circuit above, or in the editor it opens.
- Read DC and AC volts, DC and AC amps, ohms, continuity, diode, capacitance, frequency and duty
- Find which end of an LED is which on the diode range
- Measure a resistor, then see what a parallel path does to the reading
- Blow the fuse in the amps jack, and fit a new one
- Use HOLD, MIN/MAX and a manual range, as on a real meter
- Put a meter and a scope on the same circuit
What the running circuit shows
Four readings from one unpowered board.
On the diode range the meter pushes 1 mA through the LED and shows what that took: 1.42 V. Swap the leads and it reads OL, because the LED blocks that way, which is how you find the anode on a part with no markings. On the capacitance range the same two leads, across the capacitor in the same two columns, read 1.00 µF either way around.
On ohms, across the 4.7 k and the 10 k wired in parallel, it reads 3.20 k: the right answer for what is between the leads and the wrong one for either resistor. Take out the two jumpers that put the 10 k beside it and the same leads read 4.70 k. On continuity, across the wire link, it reads 0 and beeps; across the resistors it stays quiet, because the beeper trips only under 30 ohms.
How the meter is modeled
It changes the circuit, as a real one does.
Turning the dial changes what is between the leads. Volts is 10 megohms from V to COM, so it really loads a high-resistance node. Amps is a 1 ohm shunt with a 2 A fuse behind it: 20 mV of burden at an LED’s 20 mA, and put the A jack across a supply and the fuse blows in ten milliseconds, after which the current range reads zero through everything. Ohms pushes a 30 µA test current, capacitance charges with 2 µA, and the display updates four times a second.
What it leaves out: noise, drift and an accuracy specification, so the last digit never dances and the reading is the solver’s own number. AC above about a kilohertz is under-sampled and reads low, a bandwidth limit in miniature. And one known disagreement: a real meter on a real red LED reads nearer 1.6 V on the diode range, not 1.42 V, because the LED model is fitted at 20 mA and is too soft a decade lower. Mokxi’s accuracy notes record it rather than rounding it away.
Questions
Is it free?
Yes. The circuit on this page, every part in it and the editor it opens in are on the free plan, with no card.
Do I need an account?
No. The circuit runs the moment the page does, and the editor opens without one. A free account is only for saving a project to the cloud and sharing it by link.
Can I measure current with the virtual multimeter?
Yes, as you would on a bench: break the circuit, turn the dial to amps and put the red lead in the A jack, so the meter sits in the gap. Put it across a supply instead and the 2 A fuse blows, and the face says so.
Why does the meter say IN CIRCUIT on ohms?
Something is driving the leads. Ohms works by pushing the meter’s own small current, so the reading only means anything with the power off. Turn the supply off or lift the part out, and measure again.
Is there an analog multimeter?
No. The meter is digital, with a four-digit display. To watch a value that moves, clip the scope to the same node.
More simulators
Each one opens on a circuit that is already running.
Turn the dial
Open the circuit, move the leads and read the meter. Nothing to install, and no account needed.