Voltage Conversion — µV · mV · V · kV · MV
Universal voltage converter built around an ascending staircase widget. Six lit steps climb from EEG biopotential (50 µV) through Type-K thermocouple (4 mV), AA battery (1.5 V), USB-C PD (20 V), mains 120/240/480 V, EV traction packs (400 V), bulk transmission (500 kV) and lightning (100 MV). A red dashed line marks the NFPA 70E 50 V shock-protection boundary. Formula: V_to = V_from × (factor_from / factor_to). V = I × R per Ohm; named after Volta 1800.
Quick Conversion
Formula: V_to = V_from × (factor_from / factor_to); 1 µV=1e-6, 1 mV=1e-3, 1 kV=1e3, 1 MV=1e6 V · V = I·R
Real-world voltage presets (EEG µV → lightning MV)
Conversion Table (V base)
| V | mV | µV | kV |
|---|---|---|---|
| 0.005 | 5 | 5.00e+3 | 0.0000 |
| 0.05 | 50 | 5.00e+4 | 0.0001 |
| 1.5 | 1,500 | 1.50e+6 | 0.0015 |
| 5 | 5,000 | 5.00e+6 | 0.0050 |
| 12 | 12,000 | 1.20e+7 | 0.0120 |
| 24 | 24,000 | 2.40e+7 | 0.0240 |
| 48 | 48,000 | 4.80e+7 | 0.0480 |
| 120 | 120,000 | 1.20e+8 | 0.1200 |
| 240 | 240,000 | 2.40e+8 | 0.2400 |
| 480 | 480,000 | 4.80e+8 | 0.4800 |
| 1000 | 1,000,000 | 1.00e+9 | 1.0000 |
| 13800 | 13,800,000 | 1.38e+10 | 13.8000 |
Need RMS / peak / peak-to-peak? RMS voltage solver →
Formula card
V = I × R · P = V × I · V_RMS = V_peak / √21 V = 1 J/C — the work per unit charge to move charge through a potential difference.
1 µV = 10⁻⁶ V1 mV = 10⁻³ V1 kV = 10³ V1 MV = 10⁶ VSELV: ≤50 V AC / ≤120 V DCWorked: US mains 120 V RMS → 169.7 V peak → 339.4 V p-p. Above 50 V — qualified electrical worker only per NFPA 70E Article 130.
Alessandro Volta's 1800 pile and the unit that defines safety
In 2026, an NFPA 70E qualified electrician approaching a 480 V three-phase panel for arc-flash analysis needs a single converter that maps the EEG µV signal of a heart monitor against the 169 V peak of mains and the 100 MV of nearby lightning. The voltage staircase is that converter.
Alessandro Volta (1745-1827) was a professor of experimental physics at the University of Pavia when, in 1800, he announced the voltaic pile to the Royal Society of London in a letter to Joseph Banks. Stacking alternating disks of zinc and copper separated by brine-soaked cardboard, Volta produced the first sustained electric current — replacing the Leyden-jar "static" demonstrations of Franklin and van Musschenbroek with continuous chemical electromotive force.
The voltaic pile revolutionized chemistry within months. Humphry Davy at the Royal Institution used a 250-cell pile to isolate sodium and potassium in 1807; Faraday's 1831 induction experiments and Ørsted's 1820 discovery that current deflects a magnetic needle both depended on Volta's pile as the only stable current source available. The 1881 International Electrical Congress in Paris named the unit "volt" in his honor; the 9th General Conference on Weights and Measures (CGPM) in 1948 codified the volt as the SI derived unit V = W/A = kg·m²·s⁻³·A⁻¹.
Modern voltage spans 14 orders of magnitude. The smallest practical voltages are biopotentials — EEG scalp signals at 10-200 µV, ECG R-wave at 0.5-5 mV — measured by instrumentation amplifiers (Texas Instruments INA333, Analog Devices AD8232) with common-mode rejection above 100 dB. Type-K thermocouples generate ~41 µV/°C per ASTM E230, requiring cold-junction-compensation ICs (Maxim MAX31855) for temperature readout.
Battery voltages cluster around the 1.5 V alkaline cell, 3.7 V lithium-ion, 12.6 V lead-acid, 48 V telecom rectifier, 400-800 V EV traction pack. The 800 V Porsche Taycan / Hyundai E-GMP / Audi e-tron GT platforms halve conductor cross-section for the same DC fast-charging power — enabling 350 kW Ionity / Electrify America chargers per SAE J1772 + J3068 + the IEC 61851-23 standard. Below 50 V is the SELV range; above is the qualified-electrical-worker domain.
Mains voltage is regulated globally. ANSI C84.1-2020 defines US service voltage range 114-126 V (± 5%) and utilization voltage 110-125 V (-8.3% to +4.2%); distribution transformers tap-change to keep customer-side voltage in range. IEC 60038 specifies 230 V ± 10% in EU. The voltage-drop calculator sizes feeders to maintain these limits across long runs.
High-voltage transmission climbs into the kV decade. NERC FAC-008 reliability standards govern the bulk electric system (BES) — generally 100 kV and above — covering sub-transmission at 69-138 kV, transmission at 230 kV, EHV at 345/500/765 kV. The current world record for AC transmission is 1100 kV UHVAC in China (State Grid Corporation); HVDC reaches ±800 kV on the Xiangjiaba-Shanghai link. Insulation classes (BIL, basic insulation level) scale with system voltage per IEEE C57.12.00.
At the top of the staircase, lightning develops 100 MV cloud-to-ground before air-breakdown initiates the leader stroke. Air ionizes at ~30 kV/cm; over a 3-km cloud height the integrated potential is 90-300 MV. NFPA 780 lightning protection systems divert strike current via Franklin air-terminals and Faraday cages; ground potential rise (GPR) during a strike can exceed 1 MV instantaneously, requiring equipotential bonding per NEC 250 and IEEE 80 (substation grounding). From Volta's 1800 zinc-copper pile through the 2019 SI redefinition that anchors the volt to the Josephson junction frequency-to-voltage exact relation V = h × f / (2e), every step on the staircase traces back to natural law.
How to use the voltage staircase
- Pick the active unit pill. µV, mV, V, kV or MV — the five unit buttons below the staircase.
- Type the voltage value. The staircase lights up to your step; a cyan YOU marker appears above the matching step.
- Watch the 50 V danger line. The red dashed boundary marks the NFPA 70E shock-protection limit — above it, the staircase's right half glows red and a DANGER banner appears.
- Tap a real-world preset. 12 named voltages from EEG biopotential to cloud-to-ground lightning — each lights its own step.
- Save the reading. Press Save to push the voltage into the per-tool localStorage history for later comparison.
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What staircase users say
“The 50 V danger boundary on the staircase is exactly the visual I want apprentices to internalize before their first energized work. Pairs with my arc-flash slide deck — the EEG µV preset at the other end shows the human-scale context perfectly.”
“400 V vs 800 V pack vs 480 V three-phase AC service is the exact conversation I have at every site walk. The EV pack and 480 V industrial presets side-by-side on one staircase is the diagram I've been screenshotting into customer reports.”
“EEG 50 µV, ECG 2 mV, mains 120 V on one staircase explains the 5-decade analog-front-end design challenge in a single image. The Type-K thermocouple FAQ at 41 µV/°C is also exactly the spec sheet I reference daily.”
“The kV → MV step with the 500 kV transmission preset and the Josephson-junction MV-measurement FAQ is metrology gold. I cite NIST traceability to customers; this page makes the chain visible.”
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