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Using the Multimeter
The built-in multimeter is a two-probe diagnostic tool for answering questions about one point, two points, or a passive path in a circuit. It is available in the full workbench and interactive article embeds. The meter and its probes do not alter the circuit. They are not part of the circuit document, but a project can carry a starting setup for the meter (see below), so a published circuit can open with the meter already connected.
Select the meter icon in Desk tools. Drag the Multimeter title bar to move the panel.
To place a probe:
- Select Red or Black.
- Select a breadboard hole, component terminal, supply terminal, or other circuit point.
- Look for the colored probe marker showing the exact selected point.
Select a probe button again whenever you want to move it. Press Escape or M to cancel probe placement.
The reading is always interpreted from red to black. Reversing the probes reverses the sign of voltage and current readings, just as it does on a physical meter.
A lesson file or a project's desktop can carry a starting setup for the meter: whether it is open, its mode (voltage, resistance, continuity, current, capacitance, inductance), and the two points the probes sit on.
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Lessons: add a
multimeterblock besideoscilloscopein the lesson file, withredandblackset to desk addresses such asbb2.e12orpsu1.+. -
Projects: a desktop in the
.chiphippofile may carry"instruments": { "multimeter": { ... }, "oscilloscope": { ... } }. The block is optional, and files without it load as before. -
Specs: a spec can say
"instruments": { "multimeter": { "mode": "voltage", "red": "R1.1", "black": "R4.2" } }, naming probes by part and pin. The build tool turns those into hole addresses and refuses a probe that points at nothing.
Published circuits (an article's embed, and the page its "Open full workbench" link opens) run on the Spice Lite engine, so the meter reads solved voltages and currents. Move the probes any time; the setup is only where the meter starts.
V DC reports the red-probe voltage minus the black-probe voltage. Run the circuit before relying on a live voltage reading.
- Put black on circuit ground and red on a signal to measure that signal.
- Put the probes across a component to measure its voltage drop.
- A negative reading means the red probe is at a lower potential than black.
- The ordinary logic engine supplies nominal LOW/HIGH values.
- Spice Lite uses solved circuit voltages, including TTL output levels, supply droop, and analog nodes.
Voltage mode is usually the best first check when a circuit is powered but not behaving as expected. Confirm the supply first, then follow the signal through the circuit.
A DC reports current through a component lead known to Spice Lite. Place a probe on a resistor, LED, inductor, switch, chip output, or supply lead that has a modeled branch current.
Unlike a physical ammeter, the virtual meter does not require you to break the circuit and insert a zero-ohm current path. If neither selected point has a known branch current, the display remains open rather than inventing a value.
Use current mode to check LED current, resistor or load current, total supply loading, current-limit behavior, and whether a logic output is being overloaded. Enable Spice Lite for meaningful analog current values.
Stop the circuit, choose Ω, and place the probes across the passive path of interest. The meter calculates equivalent resistance, including supported series and parallel resistor networks and an inductor's winding resistance.
An open reading means no resistive path connects the probes. Resistance mode is useful for finding a wrong resistor value, an unintended open path, or a network whose equivalent value is not what you expected.
Stop the circuit and choose Continuity. A path of 50 Ω or less produces a short beep; an open path is reported as open.
Continuity is useful for checking breadboard rows, power rails, jumper routes, switch contacts, connector paths, and accidental missing connections. It is a connectivity test, not a logic-state test. A LOW signal is not automatically the same thing as a short circuit.
Stop the circuit and choose C. The meter calculates equivalent capacitance between the probes, including supported series and parallel capacitor networks.
Capacitor ESR is intentionally omitted because Chip Hippo capacitors are ideal components without simulated aging or faults.
Stop the circuit and choose L. The meter calculates equivalent inductance for supported, uncoupled inductor networks, including series and parallel combinations. Coupled inductors and transformer measurements are outside the current model.
- Stop the circuit and use Continuity to verify the intended path.
- Use Ω to catch an incorrect or missing resistor network.
- Run the circuit and use V DC from ground to the supply and signal nodes.
- Enable Spice Lite and use A DC when loading, current limits, LEDs, or analog behavior matter.
- Reverse the probes if you want to confirm polarity; the sign should reverse.
Neither probe is on a lead with modeled branch current, or Spice Lite is disabled. Move a probe to a modeled component lead and make sure Spice Lite is active.
The red probe is at a lower potential than the black probe. This is a valid reading, not an error. Swap the probes if you want the opposite polarity.
The selected holes may look adjacent while belonging to different breadboard strips, a switch may be open, or a jumper may terminate one row away from the intended point.
Stop the simulation first. Passive measurements are intended for an unpowered circuit.
ESR, component aging, probe resistance, and meter burden are not currently modeled.
Close the panel with its × button or select the toolbar meter icon again.