Current

Related wiki pages: Voltage, Resistance

What is current?

Simply, current is the flow of electric charge through a conductor.

Conventional Current

The notion of conventional current was started by Bejamin Franklin who sought to decribe the phenomenon of static electricity saying that charge (electrons) could be "rubbed off" some materials by others. He proposed that charge was transferred from wax to wool when they are rubbed together. He described the wool as being "negative" or having a deficiency of charge which allowed the transfer to take place. These experiments occurred well before the nature of electrons was dicovered, by which time his descriptions had taken a firm hold in the scientific community.

Hence, conventional current is said to flow from positive to negative.

Electron Flow Current

We now know that electrons carry an negative charge, and that similar charges repel. Hence, in an electic circuit, negative charge (and electrons) will move from the more negative end of the circuit to the more positive.

Does it matter which one we use?

In simple circuis the answer is no. Many circuits however contain "polarised" components that only work properly if they are placed in the circuit in a particulat orientation. One example is the diode. Polarised devices are usually semiconductors but do include electrolytic capacitors.

How is current measured?

Direct and Alternating Current

External links:

• wikipedia article

Electronic Theory
Physical quantities	Current * Gain * Impedance * Power * Q of a circuit * Radiated Power Measurement * Reactance* Resistivity * Resonance * Voltage
Components	Baluns * Bipolar-Junction Transistors * Capacitors * Diodes * Inductors* Lasers * Microphones * Resistors * Transformers * Wire
Circuits	Attenuators * Digital Signal Processing (DSP) * Dummy load * Filters * LC filters * Power Supply Design * Rectifier Circuits
Design	Amplifier Design * Oscillator Design
Electromagnetic Waves	Relative power (Decibels) * Harmonics * Interference and BPL