AC vs DC : Which one is very Lethal to Humans?

AC vs DC

AC and DC are the two forms of current which we use in our daily life. You might have a question that which one among these AC vs DC will be very dangerous to the humans. In fact there exists many theories to justify that this specific form of current is very dangerous comparing to the other one. But still the debate on this thing seems to be continuing and still there is no solid proof to point out one form of current is lethal than the other one. This article intend to explain the effects of these two forms of currents in a human body and attempt to bring out the dangerous one into the spotlight.


AC Signal
  • AC is alternating in nature, it undergoes change in magnitude with respect to time and takes the form of a sine curve.
  • AC continuously changes its flow direction when flowing through a circuit.
  • AC signal posses some frequency and each country uses AC of different frequency.
  • The Voltage or Current value of a AC is RMS (Root mean square) and thus the peak value of AC is usually 1.4 times the RMS value.


DC Signal
  • DC is direct in nature, it does not undergo change in magnitude with respect to time. 
  • DC is Unidirectional, therefore flows only in a single direction. 
  • DC signal does not posses any frequency.
  • The maximum voltage in a DC will always remain the same.


  • AC tend to contract the body muscles repeatedly since it posses frequency. It can also fibrillate human heart, imagine a human heart fibrillates at the frequency of a AC signal ! Deadly Isn’t it?
  • AC can cause current to enter and exit the body without closed path, therefore it can easily pass through the vital organs in our body.
  • AC peak value is 1.4 times the RMS value so a 220V AC supply is going to 308V before coming down to zero and then changes its direction. So the human experience high voltage shock in case of AC.


  • DC is continuous in nature hence it will contract the muscles continuously and therefore the chance of relaxing the grip from the conductor is less. This is known as “Can’t let go” factor of DC.
  • DC is said to cause electrolysis in the body fluids, therefore the person experienced a shock have the risk of dying due to poisoning.


  • Both AC and DC shocks are lethal but in case of DC it requires more current to produce the same effect as AC does.
  • AC goes through a zero crossing before changing direction which is in a matter of milli seconds but DC is continuous in nature so the hold of DC is stronger than AC. 
  • AC will fibrillate the heart muscles whereas DC will froze the heart while contraction. A frozen heart have better chance of regaining the normal beat pattern than a fibrillating heart.
  • AC has higher chance of getting and exit the body without a closed path because of its bidirectional nature whereas DC cannot do that.

There are also several factors which decides the intensity of shock received by a human. Among that amplitude of current, time duration of the contact, frequency plays an important role in deciding the intensity of the shock received.


Summing up all the above things, its clear that both DC and AC are lethal when come in contact with human. Even though AC seems to have a edge over DC both are capable of ruining your day or even your life. Its like “Getting hit by a truck or falling from five storey building” , in both cases the damage will be catastrophic. So it is advised to follow proper safety measures and handle these with respect.

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