Voltage Converter

Voltage Converter

Convert between volts, millivolts, microvolts, kilovolts, and megavolts for electrical engineering, electronics, and physics work. Voltage spans an enormous range in practice — from the 10-200 uV signals produced by a thermocouple to the 765 kV of a long-distance transmission line. Keeping units straight when moving between design documents, datasheets, and measurement instruments is where this converter earns its place.

How Voltage Conversion Works

All voltage units scale through volts (V) as the SI base unit using pure powers of ten. The formula is:

result = input x (source factor in V) / (target factor in V)

Key factors:

• 1 microvolt (uV) = 0.000001 V (1 x 10^-6 V)
• 1 millivolt (mV) = 0.001 V
• 1 volt (V) = 1 V
• 1 kilovolt (kV) = 1,000 V
• 1 megavolt (MV) = 1,000,000 V

Worked Examples

Example 1 — Microcontroller supply tolerance (mV to V) A microcontroller’s datasheet specifies a maximum supply ripple of 100 mV. 100 x 0.001 = 0.1 V — used when comparing against a power supply’s ripple spec given in volts.

Example 2 — Distribution substation (kV to V) A step-down transformer secondary is rated at 13.8 kV. 13.8 x 1,000 = 13,800 V — used when calculating insulation class requirements in volts.

Example 3 — ECG signal (uV to mV) A typical ECG QRS complex peak is approximately 1,000 uV. 1,000 x 0.001 = 1.0 mV — confirms the signal is in the expected millivolt range for amplifier design.

Voltage Unit Reference Table

When to Use a Voltage Converter

• Comparing IC power supply specifications (3,300 mV or 5,000 mV) against the actual volt-labeled supply output
• Converting sensor signal levels from microvolts to millivolts when selecting an appropriate instrument amplifier gain
• Translating distribution system voltages (kV) to volts for insulation and equipment rating calculations
• Working through physics coursework that mixes SI and CGS electromagnetic units (statvolts vs volts)
• Verifying that measured voltages in different units are within the tolerance band listed in a specification

Common Mistakes

1. Treating 3.3 V and 3,300 mV as different values. They are identical — 3,300 mV = 3.3 V exactly. The error arises when someone copies the millivolt figure from a datasheet and enters it into a formula expecting volts, producing a result 1,000 times too large.
2. Confusing peak and RMS voltage. Household 120 V AC is an RMS figure. The actual peak voltage is 120 x 1.414 = 169.7 V, and the peak-to-peak swing is 339.4 V. Component voltage ratings must exceed the peak value, not the RMS value.
3. Using a plug adapter instead of a voltage converter when traveling. A plug adapter changes only the connector shape. A 120 V appliance plugged into a 240 V outlet through an adapter alone will likely be destroyed. Always check the device label for its input voltage range.
4. Applying DC voltage values to AC circuits without noting frequency. Many voltage specs (transformer ratings, motor nameplates) imply 60 Hz in North America and 50 Hz internationally. The same voltage at a different frequency can overheat inductive equipment.

Quick Reference Benchmarks

Tips

• A supply labeled “3,300 mV” and one labeled “3.3 V” are the same thing — always convert both to volts before comparing specifications to avoid off-by-1000 errors.
• When selecting voltage probe attenuation on an oscilloscope (1x vs 10x), the displayed scale changes by a factor of 10 — confirm you are reading millivolts or volts per division correctly before recording a measurement.
• For sensor signals in the microvolt range, cable shielding and amplifier noise floor matter more than conversion accuracy; get the conversion right but also verify your measurement chain can resolve the signal.
• Kilovolts are used almost exclusively for utility and high-voltage power equipment; if you see kV in a consumer electronics datasheet, double-check — it is almost always a typo for V or mV.
• The 50 V AC / 120 V DC safety threshold comes from IEC 60950 and similar standards; voltages below these levels are considered “safety extra low voltage” (SELV) for regulatory purposes.
• When calculating transformer turns ratios, express both primary and secondary voltages in the same unit (volts) to avoid ratio errors — a 13.8 kV to 480 V transformer has a turns ratio of 13,800 / 480 = 28.75:1.