Electrical Symbols, Electrical Diagram Symbols

"In electronics, a vacuum tube, electron tube (in North America), tube, or thermionic valve or valve (in British English) is a device controlling electric current through a vacuum in a sealed container. The simplest vacuum tube, the diode, contains only two elements; current can only flow in one direction through the device between the two electrodes, as electrons emitted by the hot cathode travel through the tube and are collected by the anode. Addition of a third and additional electrodes allows the current flowing between cathode and anode to be controlled in various ways. The device can be used as an electronic amplifier, a rectifier, an electronically controlled switch, an oscillator, and for other purposes.
Vacuum tubes mostly rely on thermionic emission of electrons from a hot filament or a cathode heated by the filament. Some electron tube devices rely on the properties of a discharge through an ionized gas." [Vacuum tube. Wikipedia]
"The EL34 is a thermionic valve or vacuum tube of the power pentode type. It has an international octal base (indicated by the '3' in the part number) and is found mainly in the final output stages of audio amplification circuits and was designed to be suitable as a series regulator by virtue of its high permissible voltage between heater and cathode and other parameters. The American RETMA tube designation number for this tube is 6CA7. Russian analog is 6P27S (Cyrillic: 6П27C )" [EL34. Wikipedia]
This circuit diagram sample was redrawn from the Wikipedia Commons file: EL34 schematics (circuit diagram).gif. [commons.wikimedia.org/ wiki/ File:EL34_ schematics_ %28circuit_ diagram%29.gif]
The example "Circuit diagram - EL 34 schematics" was drawn using the ConceptDraw PRO diagramming and vector drawing software extended with the Electrical Engineering solution from the Engineering area of ConceptDraw Solution Park.

This electrical floot plan sample shows the Power socket outlet layout.
"The term plug is in general and technical use in all forms of English, common alternatives being power plug, electric plug, and (in the UK) plug top. The normal technical term (in both British and International English) for an AC power socket is socket-outlet, but in non-technical common use a number of other terms are used. In British English the general term is socket, but there are numerous common alternatives, including power point, plug socket, wall socket, and wall plug. In American English receptacle and outlet are common, sometimes with qualifiers such as wall outlet, electrical outlet and electrical receptacle, all of these sometimes to be found in the same document. A socket may be surrounded by a decorative and/ or protective cover called a wall plate, face plate, outlet cover, socket cover, or wall cover. In some designs this is an integral piece with the socket itself, bought and installed as a single unit." [AC power plugs and sockets. Wikipedia]
The electrical floot plan example "Power socket outlet layout" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Electric and Telecom Plans solution from the Building plans area of ConceptDraw Solution Park.