Starting with **F**, the force, the most fundamental quantity that everybody can feel it and understand it, running, driving, punching, moving stuff, lifting boxes and everything that you do, you need the force. Force can be used to speed up objects so Newton’s formula: F=Ma. Newton discovered the gravitational force to explain why we are attached on the earth and this force is something that we’ve just used to but not paying attention to it. So we can rewrite the formula: F=Mg. g is the gravitational acceleration. When we jump from a height, we should also feel the force of our earth accelerating us in g. Acceleration a or g is in meters per second per second.

**E**, the electric field, is similar to the gravitational field. It is actually the force but it is the force that can apply to or act on any charge when there are some amount of charges are located somewhere and the space around it will experience the force due to them. The simplest example is a single charge which generates a E field. In other word, any unit charge near this charge can feel the force resulted from this particular charge. E field is defined as the force per unit charge or force on a unit charge at a particular location. (If no particular knowledge of what and here charges are around). A good analogy is the gravitational field. We sense the force due to our planet earth and in fact, per unit mass, the force on the mass is different at sea level of our earth and the force at some mountain top. When the mass is near the moon, both earth and the moon create a force on that unit mass. So the field can be very complicated with more sources that create the force on the unit.

**V**, the potential, is called voltage in electronics. It is similar to the potential energy when we refer to gravitational force. Under gravitional field, assuming at sea level, the force is uniform, or constant, in the direction downward. An object, or unit mass at different height, will have a different potential energy. It is calculated as mgh. PE1, potential energy 1, equals to mgh_{1}. PE2, potential energy 2, equals to mgh_{2}. If the unit mass moves from PE1 to PE2, work is done or energy is released from one potential level to another level. You probably have seen how potential energy is converted to kinetic energy in a pendulum experiment. This is just to illustrate the change in energy level or form. You can see how the force is related to the energy with this famous equation F x d = W (work or energy). F is the force and d is the distance (or height). So in electronics, the potential difference, called voltage, V, is the electromotive force to drive the electron charge. You can visualize the V is the ability to force the electron to move to a different distance at the different potential and creating work such as turning the motor, heating the air or lighting up the room.

**Q**, the charge, is what the electron carried and what the voltage pushes. it is measured in coulombs.

**I**, the electric current, or simply current, is the amount of charges moved across an area in a unit of time, standardly one second. So one coulomb moved in one second is what is an AMPERE. So you can use the mathematics to calculate how much charges are moved in an hour like Q=Ixt. For 1A current, 1 hour= 60minutes and 60×60 seconds, there will be 3600 coulombs moved. This can be the amount of charges accumulated or stored somewhere or the amount of charges creating some energy to do some work.