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Resistance: Electrical resistance describes how an electrical conductor (a wire) opposes the flow of an electrical current (flow of electrons). To overcome this opposition a voltage (a energy) must dropped (used) across the conductor (wire). Resistance can be described by ohms law: Ohms Law: R = V / I (Resistance = Voltage / Current) (resistance measured in ohms) where: Voltage [V]= the energy lost across an component (voltage measured in volts). Current [I] = the charge (electrons) flowing through an component (current measured in Amps). Electrical resistance can be thought of as sticking your hand out a car window. The faster [current] you drive the harder the wind presses [resistance] against you hand and therefore it takes more energy [voltage] to hold your hand steady. When trying to overcome electrical resistance, the electrical energy lost is turned into heat. This is how the elements of a household stove, toaster, and fan heater work. Because of the vacuum in a light bulb, the electrical energy lost is instead turned into light. It can be seen the electrical resistance plays a large role in modern life. Resistor: The resistor is the most common electronic component and is used to limit and/or control the voltage and current in an electronic circuit. Resistors are carefully manufactured to provide a predetermined value of electrical resistance which may range from 0.1 ohms to 100,000,000 ohms, depending on the application. The physical size of a resistor also varies dependant on the amount of power passing through the resistor, given by: P = V x I (Power = Voltage x Current) (power measured in watts) There are also many types of resistors including: · Variable Resistor - changes resistance when its shaft is rotated (volume knob on a stereo). · Thermistor - changes resistance when the temperature changes (used in a thermostat). · Light Dependant Resistor (LDR) - changes resistance when the lighting changes (used in children's night-lights). Resistor Example: An LED is a small red light (such as the one on the front of most TVs) and requires 2.0 volts and 0.02 amps to operate correctly. If we connected that LED up directly to a 12 volt battery, the voltage would be too high, and too much current would flow… the LED would blow up. We need to use a resistor to limit the voltage and current. But which value of resistance should the have resistor? Uses ohms law: R = V / I = (12.0 - 2.0) / 0.02 = 500 ohms (Note: the voltage across the resistor is the battery voltage minus the voltage we want across the LED) But which value of power should the resistor be capable of handling? P = V x I = (12.0 - 2.0) / 0.02 = 0.2 Watts
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What is the meaning of load resistance?
"Load resistor" is a discriptor, not a value. Any resistor can be a load resistor if it is the proper value and power for your application. So if you want a load resistor by itself, that makes no sense. A load resistor is a resistor selected for a specific purpose. For example, it you want to put a load on an audio amplifier made to drive an 8 ohm speaker to 50 watts, then your load resistor would be a 8 ohm 50 watt resistor. If you want a load resistor to terminate a 50 ohm line, you would need a 50 ohm resistor, although in this case, you probably want one that is part of a co-ax connector. A load resistor for an op-amp output is typically 2k, since most op-amps are rated for 10 volts at 5 mA. Etc, etc.
Definition for tolerance value of a resistor?
An allowable amount of variation on either side of specified measure. If a resistor is labelled as 100 ohms, with 20% tolerance, it might be anywhere from 80 to 120 ohms. If a resistor is labelled as 100 ohms with 10% tolerance, it should range between 90 and 110 ohms. If a resistor is labelled 100 ohm with 5% tolerance, it could vary between 95 and 105 ohms. A tolerance is both ways, if a measure has 10% tolerance, then the total variation is 20%, plus 10 added to minus 10. If you are talking about variation to one side alone, the term is "deviation". If a resistor is supposed to be 100 ohms and actually tests at 105 ohms, it deviates by 5%, but is within allowable variation if it is specified to be within 5% tolerance.
What is the full form of transistor?
The fullform of transistor is transfer resistor.
What is the definition of stiff voltage divider?
A voltage divider in which the base current is small compared to the current in R2 (resistor in other path to ground) is said to be a stiff voltage divider because the voltage is relatively independent of different transistors and temperature effects.
What is the meaning of LDR?
LDR refers to Light Dependent Resistor.
How resistor function in producing passiveness in closed circuit?
We know definition of Resistance, that resistor always opposes to flow of current. resistor should have input signals from source , so it generates passivity in circuit
How is the polarity of a resistor determined?
Resistors do not have a polarity. BY DEFINITION, a resistor is a device that follows Ohms law, and does so regardless of the polarity in which it is inserted into a circuit. Manufacturers of resistors do all they can to make their resistors follow that definition. One way to make a resistor have no polarity is to build it so that it is mechnically symmetrical about its two leads. Doing so will ensure that it will also be electrically symmetrical, and thus non-polarized
Define zero ohm resistor.?
A zero-ohm resistor does not exist, so we are talking about an ideal resistor. An ideal resistor is needed for description in a circuit, where we lump all wire/parasitic resistances into discrete resistors, but the wire joining two discrete resistors is considered to have no resistance. My definition: a zero-ohm resistor is an ideal resistor that does not consume energy when a current exists in the resistor. Alternatively, a zero-ohm resistor is an ideal resistor that cannot sustain any potential drop when a current is on. Thirdly, a zero-ohm resistor is an ideal resistor that will conduct an infinite current when a voltage is applied across it.
What is the power dissipated by a parallel resistor of 100 ohms with a 40v power source?
You may find it helpful to use Ohm's law and the definition of electrical power.
Is Light dependent resistor an example of resistor?
yes, a variable resistor
Who invented the resistor?
Otis F. Boykin invented the wire precision resistor and the electrical resistor.
What are resistor values defined by?
Resistor value is defined by the Resistance the resistor offers in Kilo ohms/ohms value given by color codes on the resistor.
Describe the purpose of the coloured bands on a resistor?
The purpose of colored bands on a resistor is to tell whoever is installing the resistor the amount of resistance that particuliar resistor has.
What is the function of a cement resistor?
A cement resistor is typically used as a power resistor (a resistor whose power rating is greater than 1 W).
What is the difference between an ohmic resistor and a non-ohmic resistor?
A non-ohmic resistor doesn't have a constant resistance. A ohmic resistor has a constant resistance.
Where is the alternator resistor on a 1994 Chrysler new yorker?
The alternator does not have a resistor.The alternator does not have a resistor.
Where is the ballast resistor on a 2000 Chrysler Sebring convertible?
It does not have a ballast resistor.It does not have a ballast resistor.
