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1. Electrical and Electronics Symbols and
Meanings
What are Electrical and Electronics Symbols?
Electrical symbols and electronic symbols are those symbols that
are used for drawings schematic diagrams.
Schematic Diagram – it is a fundamental two-dimensional circuit
representation showing the functionality and connectivity
between different electrical components.
Schematic Diagram of a bridge type 12V power supply
Common Electrical and Electronics Symbols

2. Electrical Symbols

5. Electronics Symbols

6. An electronic symbol is a pictogram used to represent various
electrical and electronic devices or functions, such as wires,
batteries, resistors, and transistors, in a schematic diagram of
an electrical or electronic circuit.
Electronic symbols are also known as symbol schematics because
they are used in an electronic circuit schematic.

11. NOTE : The basic idea of any electronic circuit is the flow of
electricity. This also is further categorized into two – conductors
and insulators. Conductors allow the flow of electrons, while
insulators do not.
SAFETY PRACTICES IN AN ELECTRONICS LABORATORY
What is the importance of safety precautions when working with
electronic
components?
While working with or around electrical/electronics
equipment, it is very import to work with caution and in a safe
and smart manner. The voltage and electrical currents in businesses
and homes has enough power to cause serious injury and even death.
Safe Soldering Work Practices
1. Soldering Iron Safety
a. Never touch the element or tip of the soldering iron. It
is very hot (about 400°C) and will burn.
b. Hold wires to be heated with tweezers, pliers or clamps
to avoid receiving burns from objects that are heated.
c. Keep the cleaning sponge wet during use.
d. To the extent possible, conduct soldering on a solid,
level surface and always return the soldering iron to its
stand when not in use. Never put it down on your
workbench. Be sure the iron is secure in its stand so it
cannot inadvertently dislodge onto the work surface.
e. Turn unit off or unplug the iron when not in use.
Soldering stations that feature an automatic shut off not
only extend the life of tip, iron and station, but
provide an additional measure of fire safety.
2. Exposure
Avoid inhalation of soldering smoke/fumes. The smoke formed
during soldering is mostly from the flux. Inhalation of flux
fumes during soldering may cause irritation and damage of
mucous membranes and respiratory system. Eyes may become
irritated from contact with smoke from soldering.

12. To reduce exposure:
a. Conduct work in a well-ventilated area.
b. Avoid breathing fumes/smoke by keeping your head to the
side of, not above, your work. The Addition of a small fan
positioned behind the worker to blows air across the work
area can help move fumes away from the breathing zone.
c. Use lead free (preferable) or low lead solder whenever
possible.
d. Always wash your hands with soap and water after soldering
3. Personal Protective Equipments
To prevent burns from splashes of hot solder, long sleeve
shirts or lab coats and pants that are made of natural
fibers (cotton) and closed -toe shoes should be worn.
Safety glasses or goggles should be used when soldering and
clipping wires.
Electrical and Electronic Safety
1. Turn off power and unplug from the wall before working on
electric or electronic circuits, except when absolutely
necessary.
2. Do not use extension cords as a permanent power source. It is
against the fire code and will result in fines if these are
found by an inspector.
3. Do not work on electrical equipment in a wet area or when
touching an object that may provide a hazardous earth ground
path.
4. Turn off power and unplug equipment before checking or
replacing fuses. Locate and correct the cause of a blown fuse
or tripped circuit breaker before replacing the fuse or
resetting the circuit breaker.
5. Replace defective cords and plugs. Inspect cabling for
defects such as frayed wiring, loose connections, or cracked
insulation.
6. Remove metal jewelry, watches, rings, etc., before working on
electrical circuits.
7. Always check the electrical ratings of equipment you use and
be sure you use that equipment within its ratings.
8. Never overload circuits.
9. Never leave unprotected systems unattended.
10. Never place containers of liquid on electrical systems.

13. 11. Never defeat the purpose of a fuse or circuit breaker.
Never install a fuse of higher amperage rating than that
specifically listed for your circuit.
12. Make sure equipment chassis or cabinets are grounded.
Never cut off or defeat the ground connection on a plug.
13. Safely discharge capacitors in equipment before working
on the circuits.
NOTE : Questions regarding operation, maintenance, or safety of
electrical or electronic equipment should be directed to your lab
supervisor or an appropriate electronics expert.
Student Laboratory Safety Rules
1.Safety glasses with side shields or goggles are to be worn
at all times while in the laboratory.
2.No loose fitting clothing allowed when working.
3.No open toe shoes or sandals allowed.
4.Users must clean up area used every time work is finished.
If you have not completed your project and must leave the
laboratory you must clean area prior to leaving. Others may
need to use the area in your absence.
5.Students must clean and return all tools to proper location
when finished.
6.No tools are to be removed from laboratory without
authorization.
7.No horseplay allowed in laboratory.
8.Do not distract anyone using equipment.
9.Report all injuries immediately.
10. Floor area, where work was done, must be swept after
every use.
11. Always shut door when you leave if no one else is in
the laboratory.
12. Safety is your top priority. If you are not sure what
you are doing, “ASK”.
13. Never attempt to use equipment you have not received
training on.
14. Report any broken tools or machines immediately to
supervisor.
Always Remember . . .