Electrical Symbols — Maintenance

The vector stencils library "Switches and relays" contains 58 symbols of electrical contacts, switches, relays, circuit breakers, selectors, connectors, disconnect devices, switching circuits, current regulators, and thermostats for electrical devices.
"In electrical engineering, a switch is an electrical component that can break an electrical circuit, interrupting the current or diverting it from one conductor to another.
The most familiar form of switch is a manually operated electromechanical device with one or more sets of electrical contacts, which are connected to external circuits. Each set of contacts can be in one of two states: either "closed" meaning the contacts are touching and electricity can flow between them, or "open", meaning the contacts are separated and the switch is nonconducting. The mechanism actuating the transition between these two states (open or closed) can be either a "toggle" (flip switch for continuous "on" or "off") or "momentary" (push-for "on" or push-for "off") type.
A switch may be directly manipulated by a human as a control signal to a system, such as a computer keyboard button, or to control power flow in a circuit, such as a light switch. Automatically operated switches can be used to control the motions of machines, for example, to indicate that a garage door has reached its full open position or that a machine tool is in a position to accept another workpiece. Switches may be operated by process variables such as pressure, temperature, flow, current, voltage, and force, acting as sensors in a process and used to automatically control a system. ... A switch that is operated by another electrical circuit is called a relay. Large switches may be remotely operated by a motor drive mechanism. Some switches are used to isolate electric power from a system, providing a visible point of isolation that can be padlocked if necessary to prevent accidental operation of a machine during maintenance, or to prevent electric shock." [Switch. Wikipedia]
"A relay is an electrically operated switch. Many relays use an electromagnet to mechanically operate a switch, but other operating principles are also used, such as solid-state relays. Relays are used where it is necessary to control a circuit by a low-power signal (with complete electrical isolation between control and controlled circuits), or where several circuits must be controlled by one signal. The first relays were used in long distance telegraph circuits as amplifiers: they repeated the signal coming in from one circuit and re-transmitted it on another circuit. Relays were used extensively in telephone exchanges and early computers to perform logical operations.
A type of relay that can handle the high power required to directly control an electric motor or other loads is called a contactor. Solid-state relays control power circuits with no moving parts, instead using a semiconductor device to perform switching. Relays with calibrated operating characteristics and sometimes multiple operating coils are used to protect electrical circuits from overload or faults; in modern electric power systems these functions are performed by digital instruments still called "protective relays"." [Relay. Wikipedia]
The shapes example "Design elements - Switches and relays" 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.

The vector stencils library "Delay elements" contains 12 symbols of delay elements for drawing electrical schematics and electronic circuit diagrams.
"An analog delay line is a network of electrical components connected in series, where each individual element creates a time difference or phase change between its input signal and its output signal. It operates on analog signals whose amplitude varies continuously. An example is a bucket-brigade device. Other types of delay line include acoustic, magnetostrictive, and surface acoustic wave devices. A series of RC networks can be cascaded to form a delay. A long transmission line can also provide a delay element. The delay time of an analog delay line may be only a few nanoseconds or several milliseconds, limited by the practical size of the physical medium used to delay the signal and the propagation speed of impulses in the medium." [Analog delay line. Wikipedia]
The symbols example "Design elements - Delay elements" 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.

The vector stencils library "Transmission paths" contains 43 symbols of power transmission paths, electronic circuits, bus connectors and elbows, terminals, junctions, and concentrators.
Use it to annotate electrical diagrams, electronic schematics and circuit diagrams.
"A physical medium in data communications is the transmission path over which a signal propagates.
Many transmission media are used as communications channel.
For telecommunications purposes in the United States, Federal Standard 1037C, transmission media are classified as one of the following:
(1) Guided (or bounded) - waves are guided along a solid medium such as a transmission line.
(2) Wireless (or unguided) - transmission and reception are achieved by means of an antenna.
One of the most common physical medias used in networking is copper wire. Copper wire to carry signals to long distances using relatively low amounts of power. The unshielded twisted pair (UTP) is eight strands of copper wire, organized into four pairs.
Another example of a physical medium is optical fiber, which has emerged as the most commonly used transmission medium for long-distance communications. Optical fiber is a thin strand of glass that guides light along its length.
Multimode and single mode are two types of commonly used optical fiber. Multimode fiber uses LEDs as the light source and can carry signals over shorter distances, about 2 kilometers. Single mode can carry signals over distances of tens of miles.
Wireless media may carry surface waves or skywaves, either longitudinally or transversely, and are so classified.
In both communications, communication is in the form of electromagnetic waves. With guided transmission media, the waves are guided along a physical path; examples of guided media include phone lines, twisted pair cables, coaxial cables, and optical fibers. Unguided transmission media are methods that allow the transmission of data without the use of physical means to define the path it takes. Examples of this include microwave, radio or infrared. Unguided media provide a means for transmitting electromagnetic waves but do not guide them; examples are propagation through air, vacuum and seawater.
The term direct link is used to refer to the transmission path between two devices in which signals propagate directly from transmitters to receivers with no intermediate devices, other than amplifiers or repeaters used to increase signal strength. This term can apply to both guided and unguided media.
A transmission may be simplex, half-duplex, or full-duplex.
In simplex transmission, signals are transmitted in only one direction; one station is a transmitter and the other is the receiver. In the half-duplex operation, both stations may transmit, but only one at a time. In full duplex operation, both stations may transmit simultaneously. In the latter case, the medium is carrying signals in both directions at same time." [Transmission medium. Wikipedia]
The shapes example "Design elements - Transmission paths" 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.

The vector stencils library "UML interaction overview diagrams" contains 13 symbols for the ConceptDraw PRO diagramming and vector drawing software.
"Interaction Overview Diagram is one of the fourteen types of diagrams of the Unified Modeling Language (UML), which can picture a control flow with nodes that can contain interaction diagrams.
The interaction overview diagram is similar to the activity diagram, in that both visualize a sequence of activities. The difference is that, for an interaction overview, each individual activity is pictured as a frame which can contain a nested interaction diagrams." [Interaction overview diagram. Wikipedia]
"Interaction diagrams.
Interaction diagrams, a subset of behavior diagrams, emphasize the flow of control and data among the things in the system being modeled:
(1) Communication diagram: shows the interactions between objects or parts in terms of sequenced messages. They represent a combination of information taken from Class, Sequence, and Use Case Diagrams describing both the static structure and dynamic behavior of a system.
(2) Interaction overview diagram: provides an overview in which the nodes represent interaction diagrams.
(3) Sequence diagram: shows how objects communicate with each other in terms of a sequence of messages. Also indicates the lifespans of objects relative to those messages.
(4) Timing diagrams: a specific type of interaction diagram where the focus is on timing constraints." [Unified Modeling Language. Wikipedia]
The example "Design elements - UML interaction overview diagrams" is included in the Rapid UML solution from the Software Development area of ConceptDraw Solution Park.

The vector stencils library "Cisco optical" contains 19 symbols of optical devices for drawing Cisco computer network diagrams.
"Fiber-optic communication is a method of transmitting information from one place to another by sending pulses of light through an optical fiber. The light forms an electromagnetic carrier wave that is modulated to carry information. ... Because of its advantages over electrical transmission, optical fibers have largely replaced copper wire communications in core networks in the developed world. Optical fiber is used by many telecommunications companies to transmit telephone signals, Internet communication, and cable television signals. ...
The process of communicating using fiber-optics involves the following basic steps: Creating the optical signal involving the use of a transmitter, relaying the signal along the fiber, ensuring that the signal does not become too distorted or weak, receiving the optical signal, and converting it into an electrical signal." [Fiber-optic communication. Wikipedia]
The symbols example "Cisco optical - Vector stencils library" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Cisco Network Diagrams solution from the Computer and Networks area of ConceptDraw Solution Park.
www.conceptdraw.com/ solution-park/ computer-networks-cisco