0
Do semiconductor material have a very high resistance at room temperature?
Wiki User
∙ 13y ago
No. As temperature increases, resistance of semiconductors decrease.
This is because semiconductors have a small energy gap between their valence band and conduction band (in the order of 1 eV). Electrons must exist in the conduction band in order for the material to conduct but electrons exist in the valence band naturally. The electrons gain thermal energy for surroundings and jumps the energy gap from valence band to conduction band and hence, the SC material more readily conducts. As temperature increases, electrons can gain more thermal energy, more electrons can enter the conduction band and hence, resistance decreases.
Wiki User
∙ 13y ago
Add your answer:
Earn +20 pts
Why carbon is used in brushes instead of semiconductor material in motor?
There are a number of reasons, including: 1. Carbon is self-lubricating. 2. Carbon has a negative temperature coefficient of resistance, which means that its resistance falls as its temperature increases -which is opposite that of metals such as copper. 3. Carbon is softer than copper, so will not damage the commutator. 4. Carbon will acquire the shape of the commutator segments and, so, will ensure maximum contact with them.
What are the difference between semiconductors and semimetals?
A conductor is just that - something that conducts electric current. A semiconductor, however, is a material that can be and is used because by doing some things to it, we can cause its resistance to vary dramatically over a fairly wide range of values. We can cause it to conduct with little resistance, and we can cause it to resist current flow completely and prevent current from flowing. The material is a semiconductor, and it "sort of" conducts - either well or poorly or something in between, depending on how the device is made and on what we tell it to do. Conductor will pass electrons by the laws of electrical conductivity. Semiconductor will pass electrons basically only one way.Conductors, like copper, are materials that simply conduct electricity from point A, such as the negative terminal of a battery, to point B.Semiconductors are materials that conduct electricity from point A to point B, but have high high resistance. Many conductors can be modified to have unique properties when electricity is applied, such as in transistors. Put simply, semiconductors have an electrical conductivity somewhere between that of conductors (gold, copper) and insulators (wood, rubber).A conductor allows an electric current to flow through it equally well in either direction. The amount of current which flows depends only on the amount of resistance of the conductor and on the amount of voltage applied across it. The direction of flow can always be considered as being from the positive to the negative pole of the source of the voltage applied, so the direction of flow through a conductor is always determined by which end of the conductor is connected to the positive pole of the source. A semiconductor allows an electric current to flow very strongly in one direction (this is known as the forward current) and very weakly in the opposite direction (which is known as the reverse current). The amounts of current which flow in each direction depend partly on the amount of the voltage applied but mainly on the forward resistance (which is relatively low) and the reverse resistance (which is always very high). So, unlike a conductor, the flow of current through a semiconductor is not the same amount of current whichever way the voltage is applied. The direction in which a semiconductor allows the forward current to flow depends on whether it is a p-type semiconductor or an n-type semiconductor. How are semiconductors made? Certain elements, such as Germanium or Silicon, are not naturally semiconductors but can be made into semiconductors by melting them and adding very small amounts of other chemicals. This process is called doping. Whether a p-type semiconductor or an n-type semiconductor is produced depends on the type of doping chemical used.
What materials are partially conductive?
conductivity is a result of free electrons meaning that they can be riped away fast and the temperature of the material. a colder material has a lower resistance and higher conductivity. materials like metallic oxides have low conductivity and materials like pure copper and aluminum have high conductivity.
Difference between a semiconductor and insulator?
The difference among Metal,Semiconductor and Insulator is written bellow-1.Metal:Substances through which electricity can pass easily is called Metal.1.Semiconductor:Substance which conductivity lies between Metal and Insulator are called Semiconductor.1.Insulator:Substances through which electricity can not pass easily are called Insulator.
What increases resistance in a wire?
Current (measured by an ammeter) and Voltage (measured by a voltmeter) R= V/I Resistance equals voltage divided by current ================================ That's wonderful, but the measurement doesn't "affect" the resistance of the wire. The factors that do "affect" the resistance ... i.e. determine what the resistance will be ... are -- substance of which the wire is composed -- dimensions of the wire: thickness and length.
If voltage is high will the resistance be high?
The electric resistance is related to the diameter and extension of the wire submitted to a determined voltage which will determine the electric current flowing into the wire.AnswerVoltage has no effect on resistance. Resistance is determined by the length, cross-sectional area, and resistivity of a material (resistivity is affected by temperature, so temperature indirectly affect resistance).
What is a material that conducts current?
Material with high resistance
What is a material that conducts electric current?
Material with high resistance
Is the material inside a light bulb a conductor or resistance?
It has high resistance.
What is a high resistance circuit?
AnswerThe resistance of a material depends on its length, cross-sectional area, and resistivity. This is expressed by the following equation:resistance = [(resistivity x length) / cross-sectional area]So, resistance is directly-proportional to the resistivity and length of the material, and inversely-proportional to its cross-sectional area. So a high resistance can be obtained by increasing the length of the material or by decreasing its cross-sectional area, or by choosing a material with a high resistivity.It's also worth pointing out that resistivity is affected by temperature. For pure metals, the higher the temperature, the higher the resistivity, so the higher the resisistance. For example, a hot (i.e. an operating) tungsten lamp will have a much higher resistance than a cold tungsten lamp.
What is the name for a material that has high resistance?
ozone
What is a material that conducts electric current slowly?
Material with high resistance
Why might you want to use a material with high resistance?
High Resistance Opposes the flow of Electricity that results into production of Heat and Light.
Which material has a greater resistance aluminum or copper wire?
Aluminium wire has high resistance than Copper.
Why carbon is used in brushes instead of semiconductor material in motor?
There are a number of reasons, including: 1. Carbon is self-lubricating. 2. Carbon has a negative temperature coefficient of resistance, which means that its resistance falls as its temperature increases -which is opposite that of metals such as copper. 3. Carbon is softer than copper, so will not damage the commutator. 4. Carbon will acquire the shape of the commutator segments and, so, will ensure maximum contact with them.
What is pure tungsten?
As a high performance material, pure tungsten has high melting temperature, high density, low vapor pressure, low thermal expansion combined with good thermal conductivity, sufficient electrical resistance and high modulus of elasticity.
Does aluminum have a high air resistance?
Air resistance depends mainly on an object's shape, not so much on the material.
