6. Electric current¶
The electric current intensity is the amount of electrons that circulate through a conductor every second.
In the electrical simulator the current intensity is represented with yellow points that move through the driver with more or less speed. The faster the points move, the more current intensity they represent.
The current intensity is related to the generator tension. In the following simulation we can see three batteries of different tension connected to three equal lamps:
- The greatest voltage battery drives electrons with greater energy, so it has more current intensity.
- On the contrary, the lowest voltage battery drives electrons with less energy, so it has less current intensity.
Amperes¶
Electrical current is measured in amperes, shortened with [A]. Since this unit is relatively large, a thousand times smaller submultiple, the milliampere, shortened to [mA], is sometimes used. The following table lists typical currents for several common circuits in our environment:
| Component | Current [A] |
|---|---|
| Power indicator LED. | 10 milliamperes |
| Led type torch | 100 milliamperes |
| Smartphone working. | 1 ampere |
| Electric air heater. | 10 amperes |
Ammeter¶
An ammeter is an electrical apparatus that allows measuring the current intensity that circulates through a circuit. The ammeter is always connected in series with the element that you want to measure, so it is necessary to cut the circuit to be able to insert it.
To simulate an ammeter we must choose it from the menu Draw... Meters and Labels... Add Ammeter...
In the following simulated circuit, add three ammeters that measure the current flowing through each of the three lamps in the circuit:
Exercises¶
- What is the intensity of electric current?
- How does current intensity relate to electrical voltage?
- What current in amperes are consumed by typical circuits? Name at least three.
- What is an ammeter? How should it be connected to measure current?