Is Lightning AC or DC?. Lightning is one of nature’s most dramatic displays, characterized by intense electrical discharges that light up the sky and release massive amounts of energy. It occurs during thunderstorms when electrical charges within clouds or between clouds and the ground equalize, producing a powerful current.
Lightning is more than just a visual spectacle—it serves as a reminder of the incredible energy forces that exist in nature. But is lightning AC (Alternating Current) or DC (Direct Current)? To answer this, we must delve into its science and electrical properties.

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What is Lightning?
A lightning flash consists of several shorter discharges, each lasting less than a millisecond, which together form a full discharge that lasts approximately 0.2 seconds. Multiple lightning flashes occurring in rapid succession are referred to as a stroke. Strokes happen so quickly that the human eye often cannot distinguish the entire sequence of flashes clearly.
Lightning is a natural electrostatic discharge that occurs between two electrically charged neighboring clouds (known as a Direct Stroke) or between electrostatically charged clouds and the earth (known as an Electrostatic Induction Stroke), often accompanied by thunder. This discharge can release billions of joules of energy, generate extremely high temperatures (up to 30,000°C), produce plasma, and emit magnetic radiation and flashes of visible light due to the rapid movement of electrons. There are various types of lightning, including thundercloud lightning, head lightning, and dry lightning.
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In essence, lightning is an electric discharge that appears as flashes and sparks within charged clouds. A single lightning flash may include multiple strokes, extending from 1 to 100 kilometers in length, and typically includes 4 to 40 strokes per flash. The time between individual strokes in a flash ranges from 20 to 700 milliseconds.
A lightning stroke can discharge up to 106 volts and between 50,000 to 250,000 amperes in about 106 seconds, making it more like an impulse signal than either AC or DC.
This demonstrates that lightning consists of strong, high-magnitude strokes that occur in rapid succession, lasting only a fraction of a second, hence, lightning is not AC or DC but a series of transient impulse signals.

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What does it mean by a lightning strike?
A lightning strike is the sudden glimpse of a huge light spark in the sky. As we all know that the clouds contain electric properties. Again, the collision between the clouds results in this phenomenon. This electric phenomenon takes place due to the collision between two clouds or even clouds and land.
During this time, due to the rise and fall of air pressure around the area, we can hear a loud noise.
Characteristics of Lightning
A typical lightning flash is an intense electrical discharge. Its power, voltage, and current can vary, but on average, a single lightning flash possesses the following characteristics:
- Power: Moderate lightning strikes can produce approximately 1.2 giga watts (GW) which is equal to 1 billion watts during the peak of the strike.
- Voltage: A lightning flash carries between 100 million and 1 billion volts (100 MV to 1 GV).
- Current: Normal lightning strikes may have electric currents ranging from 30,000 to 300,000 amperes (30 kA to 300 kA).
- Heat: A lightning can generate and heat up the surrounding air up to 50,000°F (27760°C ) which is 5 times hotter than the surface of the sun. This is because the energy produced by lightning strikes tuns into heat and disperse making the surface of water positively charged.
- Noise & Sound Level: The sound pressure of intensive thunder can reach up to 190 dB in the air and 260 decibels (dB) per meter in the water, which is loud enough to cause hearing loss in humans. In extreme cases, the intense sound wave can potentially harm fish in nearby bodies of water.
- Water: A single thunderstorm can release up to 125 million gallons of water.
- Height: A large cumulonimbus cloud (thundercloud) can tower as high as 15 miles (approximately 24 km), which is three times the height of Mount Everest.
- Number of Thunderstorms: At any given moment, there are approximately 2,000 thunderstorms occurring worldwide.
- Number of Deaths & Injuries: On average, about 43 people in the United States die from lightning strikes each year. Over the past 34 years, lightning has caused 6,000 fatalities in the U.S. According to NWS Storm average data from 2009 to 2018, 27 deaths and 243 injuries were reported. This resulted in a total of 27 fatalities.
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Why Lightning Can’t be AC?
An AC (Alternating Current) signal continuously changes direction and magnitude over time, flowing in one direction during the first half of a cycle and in the opposite direction during the second half. In contrast, the waveform of lightning does not resemble the sinusoidal pattern of AC voltage and current .

Impulse wave shape parameters,
- T1 = Front time for switching impulses (Front time is the time taken for the wave to reach its Peak value.)
- T2 = Front time for lightning impulses
- T3 = Time to half value (tail time or time to half of the Peak value)
While:
- The front time for a standard lightning impulses is 1.2 μs while its tail time is 50 μs.
- Tolerance allowed in peak value is ±3%.
- The tolerance allowed for front time is ±30% and that for tail time is ±20%.
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Lightning is more like a sudden short circuit between clouds or between clouds and earth due to high charge density rather than a potential difference. Additionally, lightning acts like a capacitive discharge, with current flowing from positive to negative as in a capacitor, meaning the charge flows in one direction (unipolar), which is why lightning cannot be AC.
Why Lightning Can’t be DC?
A DC (Direct Current) signal has a constant magnitude and does not change polarity or direction over time. To be classified as DC, a signal typically has a ripple factor of less than 3%, with minor fluctuation in magnitude.
A signal can be DC if the ripple factor is less than 3% and the magnitude is ±3 during a time period.
However, lightning frequencies range from 1 kHz to 1 GHz, while DC has no frequency. Lightning also exhibits characteristics of both AC and DC components, with unidirectional, spiky unidirectional pulses that resemble irregular AC signals more than steady DC. That’s the reason why lightning can’t be DC.

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The above discussion proves that lightning is a brief, intense phenomenon with waveforms that differ from standard AC or DC waves. Its signal and waveform characteristics resemble impulse signals rather than continuous AC or DC, which is why lightning is described as an impulse phenomenon.
FAQs About Lightning : AC or DC?
1. Can we harness lightning for power generation?
Harnessing lightning is challenging due to its unpredictable nature and immense energy released in a fraction of a second.
2. Why do people think lightning is AC or DC?
The confusion arises from lightning’s resemblance to DC in its direct discharge phase and AC in its oscillatory return strokes.
3. What is the voltage of a typical lightning strike?
A lightning bolt can generate up to 1 billion volts and carry currents of 30,000 amperes.
4. Does lightning alternate directions during a strike?
Yes, during return strokes, the current may oscillate, giving it AC-like characteristics.
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