Voltage, Current and Resistance

     

Voltage

         Voltage is expressed in terms of volts (V) which has a relationship of 1 volt is equal to 1 Joule per Coulomb. Voltage is defined as " The work required per unit charge to move charges ".  Almost ALL basics circuits contain a voltage source such as the battery, similar to diagram shown below. This picture to help us to understand the idea of how voltage works. 

                  The voltage is like a piston which pushes the "fluid" through a pipe. This is representing the voltage pushing current through the circuit. 

Current

               Current is "The rate of flow of electrons through a circuit".  when you have a battery which is connected to a wire pushing those electric charges, it creates a current. Current can be thought of as the amount of charge that passes through a space per unit time (a second usually). Current is read in the unit of ampere (A). 1 Ampere is equal to 1 Coulomb per second.

              

                   From the picture above, the current flow moves around the completed loop of the circuit. If the voltage was kept at a constant ,then the current would be higher with the less amount of resistance.

Resistance

                     Resistance is " The opposition to the flow of electrons ". FOR EX- The rocks in the river that slow down the movement of the water,and decrease the  speed of the flow. Resistivity is given in Ohms per meter and an example resistivity would be 1.7 x 10^-8 (which is copper, the most commonly used wire material). 

                        The picture above is of an actual "resistor" which is a component of a circuit. The bands across a resistor are a color code scheme to label how much resistance the resistor has.