The Multimeter Dial — Every Symbol + Which Hole Each Lead Goes In

What you'll learn

• Three parts: the screen (your reading), the dial (what you measure), the holes (for the test leads). Two leads: black = the reference / ground side, red = the one that measures. Auto-range meters move the decimal point by themselves.
• V with a straight line + dashes (⎓) = DC volts: batteries, phone chargers, your Arduino.
• V with a wavy line (~) = AC volts: the wall socket — 230 V · 50 Hz (India, UK, Europe) or 120 V · 60 Hz (USA, Canada). Careful!
• Ω (omega) = ohms, resistance — only with the power OFF.
• Sound waves = the continuity beep: two points connected → it beeps. Perfect for finding broken wires.
• A triangle with a bar = diode mode: checks diodes and LEDs (often on the same spot as the beep).
• A = amps, current — the special one.
• A 9 V battery → DC volts (≈ 9 V on the screen). A battery is always DC.
• Black lead → COM (common), always. Red → VΩ for volts, ohms, beep and diodes — almost everything.
• Only for current does red move, to 10 A (or mA on some meters).
• The classic mistake: red still in 10 A, dial on volts, probes on a battery. The 10 A hole is a tiny ≈ 0.01 Ω shunt — almost a plain wire — so it is a short circuit and the fuse blows. Golden rule: after measuring current, move red back.