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Charge: Measured in Coulombs
There are two sorts of charge
- The negative particles are electrons.
- The positive particles are protons inside the atomic nuclei of atoms or molecules.
- An object that is not charged has equal numbers of positive and negative particles (Protons and Electrons).
- To charge an object, electrons have to be added (negative) or removed (positive).
- Electrostatic charge can be created by friction between objects. Rub a balloon and stick it to the wall.
- Batteries and generators produce an Electromotive Force (Voltage) that tends to cause charge to flow in a circuit.
- In a coulomb, there are 6.24 x 1018 electrons.
Current: Measured in Amps or Amperes
For the Falstad Circuit Simulation, CTRL+Click A Simple Direct Current Circuit
In options, check European Resistors and uncheck Conventional Current.
Click the switch to turn it on or off.
Alternatively view Current.txt.
Save or copy the text on the web page. Import the saved or copied text into the Falstad simulator.
Here is the new HTML5 Simulator Site.
- Current only flows if there is a complete unbroken circuit.
No current flows.
- One amp is flowing when one Coulomb of charge passes a point each second.
- A current is a flow of charged particles measured in Amperes (Amps).
- In a wire, it is a flow of electrons.
- In a battery, it is a flow of ions. (Ions are charged atoms or molecules.)
- In an N type semiconductor it is a flow of electrons.
- In a P type semiconductor it is a flow of holes. (A hole is a location where an expected electron is missing.)
- In a fluorescent light, it is a flow of ions.
- There must be a complete circuit for current to flow (no dead ends).
- If the switch is opened, there is no longer a complete circuit and no current flows.
Here is an animation showing an electric current. Click the switch to turn it off and on.