electronics summative test 1 q3
resistor
An electrical device that resists the flow of electrical current through the circuit. it comes in various sizes, types, and ratings to accommodate the needs of almost any circuit application.
the type of material used in making a resistive wire. the diamater of the wire (thickness). the length of the wire
factors that determine the resistance of the wire wound resistor
potential divider
a series circuit with two resistor and a power supply
it is less expensive than metal film resistors. it has a higher tolerance than carbon composition resistors. high voltage and high temperature applications. operating voltage up to 15kV with a nominal temperature of 350 degrees celsius.
advantages of carbon film resistors
have good characteristics for tolerance, stability, and TCR. also features low noise properties and high linearity because of low voltage coefficient.
advantages of metal film resistors
can operate at higher temperature than any other type of resistor, can be produced very accurately. has excellent properties for low resistance values and high power rating.
advantages of wire-wound resistor
x-rays, radar, layers, high voltage power supplies
applications of carbon film resistors
protection of circuits (surge/discharge protection), high voltage power supplies, current limiting, high power/strobe lighting, welding
applications of carbon-composition resistor
active filters, bridge circuit
applications of metal film resistors
circuit breakers and fuses
applications of wire wound resistors
by connecting resistors of the proper value.
by ____________________________, almost any voltage desired can be obtained.
carbon graphite and resin bonding material
composition of a carbon-composition resistor and it also determines the value of its resistance.
metal film resistor, carbon-composition resistor, carbon film resistor, wire wound resistor
different types of fixed resistors
it is expensive. requires a lot of space for mounting. it exhibits inductance in circuits that operate at high frequencies and it can cause problems to the rest of the circuit.
disadvantages of the wire wound resistor
rheostat and potentiometer
examples of variable resistors
E12 series
has 12 values and it is the most commonly used E-series for resistors. has a tolerance of +-10%, it is sufficiently accurate for almost all projects and it is sensible because most resistors have a tolerance of +- 10%
E24 series
has 24 values, more accurate with more chance of it being closer to its actual value.
tolerance
indicates the plus and minus limits of a resistor's ohmic value
variable resistor
it can be adjusted from its minimum to maximum value by turning its control.
variable resistor
it can be obtained in different case styles and power ratings
fixed resistor
it consists of only one ohmic value, which cannot be changed.
carbon film resistor
it is made out of a film of carbon (a resistive element) coating the ceramic rod (non-conducting body) in a vacuum.
metal film resistor
it is made out of a film of metal (a resistive element) coating the ceramic rod (non-conducting body) in a vacuum.
wire wound resistor
made by winding a piece of resistive (insullated metallic wire) wire around a ceramic core.
carbon-composition resistor
most commonly used type of fixed resistor that is cheap and readily available. It can withstand high energy pulses while having a relatively small size. one of its components is clay.
because it is cheap, readily available and it can withstand a high power rating despite its relatively small size
reasons why carbon-composition resistors are popular.
it is expensive
the disadvantage of metal film resistors
power rating
the maximum amount of energy it can dissipate without failing or degrading.
resistance
the opposition to the flow of electrons in an electrical circuit.
final answer is less than or equal to the given power rating
the resistor is suitable to the power rating
final answer is greater than or equal to the given power rating
the resistor is unsuitable to the power rating
bands
the stripes of the resistor color-code
variable resistor
the values can be changed over a range.
nichrome, constantan, manganin
the wire of the wire wound resistor is usually made of an alloy such as ___________________
1 ohm - 22 mega ohms
they are made in standard values that range from _________________
preferred values or E-series
to save manufacturing costs and prevent having too many resistor values available, only certain values are made
fixed resistor and variable resistor
types of resistors
the type of metal used and the thickness of the film
used to determine the resistance of a metal film resistor
resistor color-code
uses colored bands to quickly identify a resistors resistive value and its percentage of tolerance with the physical size of the resistor indicating its wattage rating.
because it determines the amount of current that will flow in an electrical circuit.
why is resistance important?
the metal film resistor does not change its value with age and its tolerance is generally better than the carbon resistors
why is the metal film resistor superior to carbon resistors?