Electronics

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Electrons atomic particles of negative charge.

Protons atomic particles of positive charge.

As in magnetism where there is north or south polarity, electricical phenomena exhibit polarity depending on whether there is negative or positive charge.

No electricity? A balance of protons and electrons.

Electricity? An imbalance of electrons and protons and thus the ability to do work, expend energy.

 

Electricity the flow of electrons in various conductive media such as metals, vaccuums, and semi-conductive solid state materials (silicon, carbon, germanium).

Charge occurs when a state of excess of electrons (negative charge) or protons (positive charge) exists in a material.

Voltage is the difference in potential between two charges and is measured in Volts.

 

Current is charge in motion as free electrons move along a conductive path towards the source of positive charge. It is electrons that move rather than protons because electrons are about 1/1840th as heavy as protons. Current is measured in amperes.

Resistance is opposition to the flow of current. With the exception of rare superconductive materials all materials exhibit some resistance to the flow of electricity through them. The fact that even a good conductor like copper wire can get hot while conducting electricity is evidence that some opposition exists to the free flow of current.

Electronic circuits all make use of three fundamental principles of electricity and magnetism. These are:

resistance

capacitance

inductance

five basic types of components used in electronics: 

Resistors

 

quality:	resistance
construction:	carbon or wound with resistance wire
function:	limit the amount of current in a circuit
unit:	of resistance (R) is the ohm

Capacitors, or condensers

 

quality:	capacitance
construction:	an insulator between two conductive plates
function:	stores electric charge, blocks direct current (DC) while passing alternating current (AC). The higher the frequency, the easier it is for the capacitor to pass it along to the next stage of the circuit.
unit:	of capacitance (C) is the farad

Inductors, or coil or choke

 

quality:	inductance
construction:	a coil of wire
function:	concentrates the magnetic field of the current in the coil. Passes a steady direct current better than an alternating one, the higher the frequency, the more effective is the choke in reducing the amount of alternating current.
unit:	of inductance (L) is the henry

Electron tubes, vacuum tube, cathode-ray tube, two electrode tubes or diodes

 

passes current in only one direction; used as a rectifier to change alternating current to direct current three or more electrode tubes used to control the flow of current between input and output electrodes to effect amplification.

Solid state devices (silicon)

Transistor used to control the flow of current between input and output electrodes to effect amplification.

Diode passes current in only one direction; used as a rectifier to change alternating current to direct current

Integrated circuits which combine transistors and diodes in one solid state device, component density has reached Very Large Scale Integration (VLSI) with hundreds of thousands of transistors on a single chip.