Electrical conductors are a fundamental part of electronics. All electronic components require a way to transport charge between themselves and other components.
Electronic components also require a way to transport charge away from themselves in order to function properly. This is why all electronic components have at least one hole or opening in their casing where charge can escape.
The term for the charge that escapes is leakage current. Leakage current is the flow of electric charge across an opening in a device, such as the opening in the casing of an electronic component.
How much leakage current an electronic component has depends on several factors, such as its size, material composition, and shape. All of these factors affect how easily charge can escape the component.
This article will discuss how to measure leakage current in electronic components and what levels are acceptable according to industry standards.
Positive charge
A conductor with a positive charge is called a positive conductor. The force that pushes a positive conductor away from ground is the same force that pulls it toward ground.
That force is the Coulomb force, which is described as the electrostatic interaction between electrically charged particles. In this case, the charged particles are electrons in the conductor and the ground.
The Coulomb force is always directed from a higher electric charge to a lower one. Since the ground has no charge, it represents the lowest charge possible. Therefore, the Coulomb force directs an electron away from ground.
Positive conductors have charges that push other charges away, so how can they be connected to ground? By placing a negative conductor next to it, then there will be two charges pulling each other toward each other and back to ground.
This happens because both are charged and therefore have an electrostatic interaction with each other.
Negative charge
A conductor with a charge is called negatively charged if that charge is negative. That means that a conductor with a negative charge has electrons flowing out of it, creating a deficiency of electrons within the conductor.
If a positively charged object comes near it, the electron flow will be reversed, and the positively charged object will be coated in negative charge. This is why we say “opposites attract” – because charges of opposite value attract each other.
So how does this work if the ground is defined as 0 volts? Well, if there are any excess electrons on the conductor, they will flow out to the ground, making the overall charge of the conductor 0.
This is why we can’t have a static shock on a floor that’s electrically grounded – all of the excess charge on your body flows to the ground, making you and the floor equal in charge.
Zero charge
If the conductor is connected to the Earth, or any other source of “ground”, then the charge on it will be zero. That is because charge can only exist on a single object, and the Earth itself is a large object with a neutral charge.
This is an important fact to remember! If you were to hold a metal rod in your hand and touch the ground, you would feel no charge. This is because your hand is also at ground level, and therefore there is no charge difference between the two.
The same goes for if you were to stand on the ground – you would be at ground level, and therefore have zero charge on you. You could not feel a difference between yourself and the Earth because you both have the same neutral charge.
Remember this: A conductor that is connected to ground has zero net charge.
Conductor and ground have the same charge
In the case of a conductor connected to the Earth, or any other lower potential, what is the charge on the conductor?
The answer is that there is no charge on the conductor!
This might sound crazy, but let me explain. A metal wire has a net charge of zero due to the process of ionization.
Ionization is when atoms are split into charged particles, or ions. These ions can be either positive or negative depending on what type of atom it was.
When a metal wire is connected to ground, all of the electrons in the wire are transferred to the Earth’s surface, leaving no charges behind. This makes the Earth’s surface and the metal wire with zero net charge. Therefore, there is no charge on either side of the connection between them.
Conductor and ground have opposite charges
The concept of ground is important in understanding charges. Ground is the term used for a complete absence of charge.
If there is no charge, then there is no force acting on it. Since there is no force on it, it does not have a direction of motion.
A ground is something that you can rely on being neutral. For instance, the Earth is considered a ground because it has an overall neutral charge due to its atmosphere and magnetic field.
When you connect a conductor to ground, the two have opposite charges. That means that one of them has a charge of +1 and the other has a charge of -1. They will repel each other and stay separate unless they are connected to something else.
Connecting a conductor to ground does not change the fact that they have a charge. It only changes what their charges are compared to something that is assumed to be neutral or devoid of charge.
Ground is a poor conductor
A common misconception is that the earth (or any other planet) is a large reservoir of electrons that can be drawn from to neutralize a charged object.
This isn’t the case at all!
Earth is a poor conductor of charge, and its not because it has any more electrons than anything else. In fact, all atoms have the same number of electrons – they’re all neutral! The difference is in how easily these atoms can transfer charge between each other.
Air is a good example of a poor conductor. It’s difficult to push air molecules away from each other, which makes it hard to transfer electric charge between them. Earth isn’t able to do this at all, which makes it an excellent grounding agent for electrical charges.
Charge the conductor with a battery
If there is a battery connected to the “ground” then the conductor will have a charge. This is due to the fact that the battery has an output charge, which flows into the ground and then back out of the ground into the conductor.
Charge can be passed from the battery to the ground and then back to the battery again. This creates a circulating flow of charge between these two elements.
The more voltage (force) put into the battery, then more charge will flow out of it and onto the ground. The harder you push water out of a hose, then more soil will get wet.
Charge can be removed from a conductor by using a resistor or “ground”. A resistor is an element that absorbs some charge that flows through it. A resistor with enough resistance will completely eliminate any charge on it.
Touch the ground with your hand
Now, let’s try a more practical experiment. Stand up and walk to the nearest wall, then touch the wall with your hand.
You just touched ground, or 0 charge! You did not notice it because you are not sensitive to charges less than 1 electron charge.
Since you are composed of atoms, each atom has at least one electron, so your body has a small amount of charges. These charges are not enough to detect on your body, but they are enough to detect on a conductor that is connected to the ground.
Now try walking across the room and touching the wall with your foot. What happens? You probably did not notice anything except for maybe feeling a little bit cooler. That is because your body does not transfer any charge to the floor.
