Ohm’s law: One of the most important laws of electric circuits: the relationship between the voltage across a component, the current in the component and the electric resistance exhibited by the component to the flow of electricity. Try to master the meaning of Ohm’s law before continuing any further. Ohm’s law is probably the most fundamental as well as the important relationship that defines the relationship between voltage and current in a circuit. Ohm’s Law: Relationship between Voltage, Current, and Load Resistance Similarly, higher voltages are more dangerous lightning is a high-intensity voltage that if directly hits someone, there is no hope for survival. You should not touch the wires (if bare) at home because if the voltage there does not kill, it definitely causes injuries and gives a disturbing shock. You can touch the two sides of a small battery (1.5 V) without any fear, while you might be cautious about doing the same for a car battery. Also, lightning during a thunderstorm has millions of volts. This official definition of volt may not be much help to understand how much 1 V is.Ī better understating is possible by considering that each small dry battery you use in your battery-operated devices is 1.5 V, the car battery is 12 V, and the electricity at home is around 115 V. Volt is defined as the value of the potential difference for which the energy of one coulomb of electric charge (i.e., the charge of 6.241 × 10 18 electrons) is one joule. Voltage is the electric potential that causes electrons to move around a closed circuit. From these numbers you can imagine what can happen if you touch the wires. Each regular switch at home is capable of carrying 15 A. That means it is possible to have a maximum current of 100 A at home. The fuse box at many homes in North America has a capacity of 100 A. One amp current is around the electric flow rate giving that much heat and intensity to that lightbulb. See how bright (and hot) the filament is when it is connected to electricity. This will gradually become clearer for you as we continue this discussion.Ĭonsider a lightbulb at home on these, “110 V, 100 W” is written. Yet you may not get a tangible feeling for how much 1 A of current is. In fact, from a mechanics view, electrons cannot go very fast, because although very tiny, they still have mass and follow the rules of motion. The reason for electricity to move very fast is the simultaneous transfer of electric charge along with a conductor. The speed of electrons does not play any role in electrical current, although electricity travels fast, close to the speed of light. It is the volume that counts more because it is the amount of electric charge that is important.

Thus, we may say a flow of 1-coulomb electricity in 1 sec is 1 A.Ĭoulomb:Measure of the amount of electricity equal to the electric charge of 6.241 × 10 18 number of electrons.įor these many electrons to move, it is not necessary that their speed be high. The amount of electric charge corresponding to this number (6.241 × 10 18) of electrons is called 1 coulomb. If 6.241 ×10 18 electrons move through a wire in 1 sec (i.e., if these many electrons pass a given cross-section of a wire during a 1 sec period), the electric current is 1 amp (1 A). In fact, electric current is the rate of the electric charge of those electrons, because we are concerned about the electric charge, not the numbers, corresponding to electrons. The electric current is a measure of the rate of flow (i.e., how many per second) of electrons.

Define current voltage resistance