I am aware that current is very dangerous and only 0.2 amps is enough to stop a heart. However I always see that high voltage is dangerous. Tasers produce a high voltage but since there is low current it is considered safe. How is it possible? According to Ohm's law, Current is equal to voltage divided by resistance (I=E/R). So if you are being tased by 10,000 volts and your resistance is only 1000 ohms, wouldn't there be 10 amps flowing through you and killing you? (10,000/1000= 10)
Electronic – How is it possible to have high voltage that is safe
currentohms-lawsafetyvoltage
Related Solutions
What you do with a current limited power supply is set to maximum properties. The power supply will regulate its output voltage in such a way that the lowest condition is met.
I drew a graph for how a current limited power supply will act with varying resistance connected. Consider a 12V power supply limited to 1A.
- The X-scale varies the load resistor from 1 to 30Ω;
- The left Y-axis and red line represents the ouput voltage of the power supply. Clearly when the resistor is too low, the power supply output voltage drops, to fulfill the 1A max output;
- The right Y-axis and green line represents the output current. Once the maximum output voltage is reached the output current will drop inversely proportional with the resistor value.
- You can clearly see voltage regulation taking over from current regulation at R=12Ω
I am confused about how pressing the switch actually changes the current being delivered to the [74HC04].
The 74HC04 has a high-impedance input. It will source or sink only miniscule currents, whether the input voltage is high or low (possibly it will sink more current at some in-between voltage, which is why we try to avoid driving it there).
So when the switch is open, there is essentially no current through the resistor. Therefore the voltage across it is 0, and the voltage at the input to the 74HC04 is VCC.
When switch is closed, it shorts the 74HC04 to ground. Since there's now 5 V across the resistor, some current (5 mA) will flow through it and everything is consistent. Still no current flows in or out of the 74HC04 input.
Best Answer
Safety standards are different for a taser from an ordinary electrical appliance.
The whole point of a taser is to have an adverse effect on the human body, and a small fraction of people who get tased do die from it. This risk is considered acceptable (by some people), since the alternative is for the taser user to use a gun or nightstick instead, either of which has risk of death.
However, if you are designing a kitchen appliance or a television set, if it has the same effect on its user as a taser, that would be a gross failure, and an unacceptable risk.