The region where resistance decreases with increase in temperature.
Friction and Air Resistance.
When the object is very light or/and the region around the object is very windy!
As temperature increases the resistance of semiconductors decreases. This means that semiconductors have a negative temperature coefficient.
Positive Temperature coefficient indicates that the resistance of material INCREASES with rise in the temperature. Resistance Temperature COefficient(RTC) is defined as increase in resistance per unit original resistance per unit rise in temperature. Temperature Coefficient of Resistance=R2-R1/(R1*(T2-T1)) Where: R2:Resistance at temperature T2 R1:Resistance at temperature T1 SO from formula it is clear that if resistance increases with temperature(T2-T1>0 and R2>R1) then Difference R2-R1 will be positive hence RTC will have positive value. But if with increase in temperature(T2-T1>0) resistance decreases(R2<R1) then difference R2-r1 will be negative hence RTC will be negative.
-- The definition of 'reverse bias' is anode negative with respect to the cathode, or negative voltage across the diode. That places the graph in negative-x territory. -- The diode simply acts as a resistor. Its unique 'diode' characteristics arise from the fact that its 'resistance' changes with different bias points, but the current through it always has the same polarity as the voltage across it. Therefor . . . -- When the voltage across it is negative, the current through it is also negative. Negative current appears on the graph in negative-y territory. -- Negative-x territory/negative-y territory is the third quadrant.
A negative resistance region is where the current goes up while the voltage goes down, or vice versa. This is a characteristic of the esaki or tunnel diode, when it is in its tunnel region.
negative resistance region
Whenever you measure resistance, the resistance itself cannot be negative!When an SCR (Semiconductor Controlled Rectifier) is not conducting, it has a high resistance between its anode and its cathode. When its gate is triggered and the SCR is conducting, it has a low resistance between its anode and its cathode.For more information about SCRs, see the answer to the Related Question (for which a link is shown below) and also the Related Link.
amplification
because that the tunnel diode is a standard pn junction diode in many respect except its highly doped pn junction so it has some characteristics in the negative resistance region another that its a standard diode
A Tunneldiode, usually made of GaAS. In a part of its curve it has a negative resistance. This means that when you increase the voltage in that region, the current will drop.
Plot a V-I curve for an ordinary resistor and you'll get a straight line with positive slope: as current goes up, so does voltage drop across the component. The V-I curve for some semiconductors features a region of negative slope. When the device is operating in this region, it exhibits negative resistance, which can be extremely useful when designing stable feedback systems.
The diode that has a negative resistance region in its voltage-current curve.
Some materials have negative temperature coefficients of resistance, and some have positive temperature coefficients. Carbon is an example of a substance with a negative thermal coefficient of resistance, so it's resistance will decrease as it gets hotter.
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Negative temperature coefficient of resistance means that as the temperature of a piece of wire or a strip of semiconducting material increases, the electrical resistance of that material decreases.
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