Voltage without knowing current

In summary, when it comes to voltage, it is important to consider the current in order to determine the level of danger. Without knowing the current, any voltage can be considered deadly. To calculate the current, one must also take into account the resistance of the body. However, it is best to treat all voltages as dangerous and to be cautious. Additionally, it is worth noting that DC voltages are more dangerous than AC due to their continuous flow of current. This was demonstrated in the historical debate between Edison and George Westinghouse, where an elephant was tragically killed in an attempt to prove the danger of AC voltage.
  • #1
elimenohpee
67
0
How do you know how much voltage is deadly without knowing the actual current? For example, a stun gun generates a 50kV with only 2 milliamps worth of current. But on the other hand, a small generator can produce 15kV of voltage. Obviously I'm going to say the generator is more deadly, but I don't actually know the current flow. Basically my question is, when reading a voltage rating, how can you really relate the total amount of energy without knowing the current?
 
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  • #2
elimenohpee said:
How do you know how much voltage is deadly without knowing the actual current? For example, a stun gun generates a 50kV with only 2 milliamps worth of current. But on the other hand, a small generator can produce 15kV of voltage. Obviously I'm going to say the generator is more deadly, but I don't actually know the current flow. Basically my question is, when reading a voltage rating, how can you really relate the total amount of energy without knowing the current?

The short, safe answer, would be to consider any voltage "DEADLY" if you have no information about the current.
 
  • #3
RonL said:
The short, safe answer, would be to consider any voltage "DEADLY" if you have no information about the current.
. . . because without knowing the current, you really don't know.
 
  • #4
elimenohpee said:
How do you know how much voltage is deadly without knowing the actual current? For example, a stun gun generates a 50kV with only 2 milliamps worth of current. But on the other hand, a small generator can produce 15kV of voltage. Obviously I'm going to say the generator is more deadly, but I don't actually know the current flow. Basically my question is, when reading a voltage rating, how can you really relate the total amount of energy without knowing the current?

You need to look at the resistance of your body. Let's say that this is about [itex]3000 \Omega[/itex], you can calculate the current flowing for a given voltage. A current of 30mA is considered deadly, but there are more factors involved, p.e. the resistance varies in case your hands are dry or not, the fact that it is DC or AC (DC is more dangerous because it does not go through zero every 50 or 60 times a second, therefore more difficult to cut), etc.

As an example consider [itex]U=230V[/itex] and [itex]R=3000\Omega[/itex], you get about [itex]77mA[/itex], so deadly, on the other hand [itex]U=110V[/itex] with the same resistance gives about [itex]37mA[/itex], so lesser change of death, but indeed dangerous. Consider every voltage as dangerous and being carefull is the best remedy.

best regards,

coomast
 
  • #5
coomast said:
DC is more dangerous because it does not go through zero every 50 or 60 times a second, therefore more difficult to cut)

In fact, Edison tried to prove otherwise! Remember the historical debate between Edison and George Westinghouse on DC versus AC ? An elephant lost it's life in the bargain when Edison electrically executed a rogue elephant with AC power to prove to the world the that AC voltages can be fatal. :wink:

regards,
Shahvir
 

What is voltage?

Voltage is a measure of the electric potential difference between two points in an electrical circuit. It is measured in volts (V).

How is voltage different from current?

Voltage and current are two different but related concepts in electricity. Voltage is the potential energy that drives the flow of electrons, while current is the actual flow of electrons through a conductor. Voltage is measured in volts (V), while current is measured in amperes (A).

Can voltage exist without current?

Yes, voltage can exist without current. This state is known as an open circuit, where there is a potential difference between two points but no flow of electrons. This can happen when a switch is open or when there is a break in the circuit.

How do you measure voltage without knowing current?

Voltage can be measured using a voltmeter, which is a device that measures the potential difference between two points in an electrical circuit. The voltmeter is connected in parallel to the component or circuit being measured, and the voltage can be read directly from the voltmeter display.

What are some practical applications of voltage without current?

There are several practical applications of voltage without current, such as in electronic devices that use batteries or power supplies to store or supply a steady voltage. Voltage is also used in electrical systems to regulate the flow of current and to power various components and devices.

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