How to Determine Electron Flow in Electronic Circuits

Electron flow (current) is the movement of charge through a circuit. The standard unit of measure for current is the ampere, defined as the amount of current required to produce a force of 2 x 10^-7 newtons per meter between two parallel conductors that are one meter apart under ideal circumstances. The following steps will show how to determine electron flow in electronic circuits.

Difficulty: Moderate

Instructions

1. Examine the nature of free electrons in a conductive metal such as copper. Many of the electrons in these metals are not bound to an individual atom. Even with a voltage source, they are able to roam freely through the metal because of thermal energy (heat). In this case, however, the flow of elections is sufficiently random that the current is negligible.

2. Observe what happens to electron flow when a voltage source such as a battery is connected to the circuit. The free electrons are forced to flow from the negative to the positive terminal.

3. Define electrical charge as a measure of the electrons that flow through a cross-section of a conductor over time. The standard unit of charge is the coulomb, which is the amount of charge carried by one ampere in one second and is equal to about 6.242 x 10^18 electrons.

4. Study the relationship between current and charge. Based on Step 3, we have Q=It where Q is the charge represented by coulombs, I is the current represented by amperes and t is the time represented by seconds.

5. Use Ohm's law to establish the relationship between current, voltage and resistance. This is given by I=V/R where I is the current represented by amperes, V is the voltage represented by volts and R is the resistance represented by ohms. This shows that an electrical circuit's current is in direct proportion to its voltage and inverse proportion to its resistance.