atomic particles of negative charge.
atomic particles of positive charge.
A balance of protons and electrons.
An imbalance of electrons and protons and thus the ability to do work, expend energy.
the flow of electrons in various conductive media such as metals, vaccuums, and semi-conductive solid state materials (silicon, carbon, germanium).
occurs when a state of excess of electrons (negative charge) or protons (positive charge) exists in a material.
is the difference in potential between two charges and is measured in Volts.
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.
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.
|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|
|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|
|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)|
used to control the flow of current between input and output electrodes to effect amplification.
passes current in only one direction; used as a rectifier to change alternating current to direct current
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.