Step 2. Voltage.
Just as important as current, "Voltage" is something that needs to be considered when powering electrical devices.
Voltage is measured in "volts", and as you may already know, the symbol for volts, is a "V". For example, "240V" is a bigger voltage than "12V".
Like "Current" is a measurement of "Amps", "Voltage" is a measurement of the difference in electrical energy between the two different parts of a circuit. The bigger this difference in energy is, the higher the voltage becomes. The best way to describe "volts", is that it is the pressure that causes a current to flow like was seen in the pictures in the previous step.
An example of this could be that you have a tank of pressurized water. This is connected to a hose. When you increase the pressure in the tank, this will make more water come out of the hose. It's that pressure that is the same as voltage. Increasing the voltage will make more current flow.
Planning and care needs to be taken when building a robots electrical system, as you may have different electrical components that require different voltages. Using the EZ-B v4 for example, using EZ-Robot HD Servos connected to the v4's digital ports can be powered with a 7.4v LiPo Battery. The black "Ground" and red "Vcc" pins helps deliver the 7.4 volts to the servo.
Now you want to use an Ultrasonic Distance Sensor (ping sensor) on the digital ports next to your servo. The ping sensor is only rated for 5 volts. You plug the sensor in and fire up your EZ-B. Chances are you will burn out the ping sensor as you are giving it "7.4 volts" which is too much power.
(Whatever voltage the battery is capable of delivering, will be the same voltage on ALL of the unregulated digital Vcc (red) pins.) on the EZ-B v4.
Possible ways around this, is to use another power source that is the correct 5v voltage, or use power converters, which will be explained in step 8.
A Voltage Summery.
Let's take a simple 4.8 to 7.4 volt servo.
! Giving it 12 volts will fry it.
! Giving it 2 volts will under power the servo and could damage it.
! Following the correct specifications for any electrical device is always advisable.