electronics PowerPoint Presentation about resistors

1. RESISTOR
Presented by: Ethan Jake Ferrer :>

2. What Is a Resistor?
• The resistor is a passive electrical component
that creates resistance in the flow of electric
current.
• In almost all electrical networks and electronic
circuits they can be found. The resistance is
measured in ohms (Ω). An ohm is the resistance
that occurs when a current of one ampere (A)
passes through a resistor with a one volt (V) drop
across its terminals. The current is proportional
to the voltage across the terminal ends. This ratio
is represented by Ohm’s law:
R=V/I

3. ResisTHOR but
couldn’t resist
SYMBOLS
The international IEC symbol is a rectangular shape
with leads at each end as shown in the figure at left. In
the USA, the ANSI standard is very common and
represents a fixed resistor as a zigzag line (shown on
the right).
IEC fixed resistor
symbol
ANSI fixed
resistor symbol

4. Overview of Types and
Materials
•Resistors can be divided by functional type as well as resistance
material. The following breakdown for the types can be made:
Fixed resistors
Variable resistors, such as the:
• Potentiometer
• Rheostat
• Trimpot

5. •Resistors for which the resistance value is dependent on a physical quantity:
Thermistors (NTC and PTC) - the resistance is a function of temperature
•Photo resistors - the resistance is a function of light level
•Varistors - the resistance is a function of voltage
•Magneto resistors - the resistance is a function of magnetic field
•Strain gauges - the resistance is a function of mechanical load
For each of these types, a standard symbol exists. Another breakdown based on the material
and manufacturing process can be made:
Carbon composition
•Carbon film
•Metal film
•Metal oxide film
•Wirewound
•Foil

6. Resistor Characteristics
Dependent on the application, the electrical engineer specifies
different properties of the resistor. The primary purpose is to
limit the flow of electrical current; therefore the key parameter
is the resistance value. The manufacturing accuracy of this
value is indicated with the resistor tolerance and is expressed
as a percentage of the resistance value (for example ±5%).
Many other parameters that affect the resistance value can be
specified, such as long term stability or the temperature
coefficient. The temperature coefficient, usually specified in
high precision applications, is determined by the resistive
material as well as the mechanical design.

7. Resistor Standards
Many standards exist for resistors. The standards describe
ways to measure and quantify important properties. Other
norms exist for the physical size and resistance values.
Probably, the most well known standard is the color code
marking for axial leaded resistors.

8. Resistor color code
Resistor with a resistance of 5600 ohm
with 2 % tolerance, according to the
marking code IEC 60062.

9. SMD Resistors
For SMD (Surface Mount Device) resistors, a numerical
code is used, because the components are too small for
color coding. SMD resistors are, just as for leaded
resistors, primarily available in the preferred values. The
size of the component (length and width) is standardized
as well, and is referred to as resistor package. An
example of an SMD resistor on a PCB is given in the
picture. The marking “331" means that the resistance has
a value of 33Ω x 101 = 330 Ω.

10. Resistor Applications
There is a huge variation in fields of applications for
resistors; from precision components in digital
electronics to measurement devices for physical
quantities. A few popular uses are described below.
• Resistors in series and parallel
• Measure electrical current (shunt resistor)
• Resistors for LEDs
• Blower motor resistor