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How can you find a resistance of resistor without DMM explain the method with the help of example?
Wiki User
∙ 10y ago
Hi
You can find the value of the resistor by using colour code printed on the resistor.
1. Hold the resistor such that the colour code starts from left.
2. Each of the colour bands present on the resistor specifies a value.
3. The first colour band represents the first significant figure, the second band represents the second significant figure and the third band indicates the multiplier. The fourth band represents the tolerance.
Gold band- 5%, Silver band-10%, No band-20%
4.Find the appropriate values for the colour by using the chart 1.
5. Find the value of the resistor by using the formula 1.
Chart1
Example:
Here first band represent brown.
Second band represent black.
Third band represent red .
Fourth band represent gold.
The value of resistor = 10 x 102 ± 5%
= 1kΩ ± 5%
Wiki User
∙ 10y ago
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Why do some circuits need resistors?
A circuit does need resistance but not necessarily a resistor. without any resistance a circuit will be considered a "short circuit" and you power source will most likely overheat. Resistance can be created in millions of different ways. This could be something such as an or any other light source but also a module such as a capacitor resistor or diode. To get to you're question more directly a circuit needs resistance to keep from shorting out. A specific module(such as an LED) would need a resistor to lower the voltage so to a point where the module can accept the power without burning out.
How does voltage remains constant in resistors connected in parallel?
It is not necessary for anything about them to be the same.All that is necessary is that they create the desired equivalent resistor, having the correct resistance and power dissipation rating without overstressing either resistor.
How do you get tolerance of resistor?
That depends on how much resistance is called for through the engineering, there is tiny resistance (mf) microfared on up huge resistance seen on electrical poles. Your circuit engineering formula dictates the needed resistance or it will just burn or not flow at all, you cannot answer the question without first asking a question..How much resistance do you need. They can be produce for virtually any tolerance.
What is the purpose of fixed resistor?
To lower the voltage and amperage in order to better fit the needs of other components.
What is the effect on the total resistance if increase in resistors in series?
That depends ... in a very interesting way ... on whether they are connected in series or in parallel. -- If the resistors are in series, then the total resistance increases when you add another resistor, and it's always greater than the biggest single one. -- If the resistors are in parallel, then the total resistance decreases when you add another resistor, and it's always less than the smallest single one.
What is the relationship between Wattage and resistance of resistor?
There is no direct relationship.Power ('wattage') is a measure of the rate at which the resistor can dissipate energy; excessive power means that a resistor cannot dissipate energy fast enough to prevent its temperature becoming excessive -excessive enough to damage the resistor.As the rate at which a resistor can dissipate energy is determined by its physical size, a resistor's power rating(maximum continuous power it can handle without exceeding its rated temperature) depends on the physical size of the resistor.On the other hand, the resistance of a resistor is notaffected by its physical dimensions, as a resistor can be manufactured to any particular value of resistance for whatever physical size is necessary to achieve its rated power.If you know a resistor's rated power and its resistance, then you can calculate the maximum continuous current that resistor can handle without overheating (using the equation: power = current squared x resistance).
Why you use resistor with variable resistor?
Often we want to easily change a resistor value, so we use a variable resistor. For example, we may want to change the resistor that controls the power sent to a LED, so we can easily make it brighter or dimmer. Often if we use a variable resistor, there is only a very narrow range that is useful. Continuing our example, sometimes we use several LEDs, and we use the variable resistor to set them all to the same brightness. In this case, the resistance range that sets the LED to be twice as bright as the the other LEDs, and the resistance range that sends so much power to the LED that it is permanently destroyed is even less useful. So we add a fixed resistor in series with the variable resistor -- the fixed resistor sets the minimum net resistance, no matter how we turn the knob on the variable resistor. In our example, the addition of the fixed resistor allows us to turn the variable resistor throughout its whole range, and the LED gets brighter and dimmer; without that resistor, a certain range of the knob on the variable resistor would allow so much power to go to the LED that it would be destroyed.
What is the output resistance of common emitter amplifier with emitter resistor and without bypass capacitor?
Without a bypass capacitor it is just equal to Rc
Reason for using wire wound resistor in electronic circuit?
There is many uses for the resistor in electronic circuits, like current limiting, voltage division, R/C oscillators and many more. Without the resistor electronics is not possible
How current passes through resistor.?
What is the current running through resistor four?1 amps..!What is the current running through resistor one? 3 amps...!What is the current running through resistor three? 2amps..!What is the current running through resistor five? 3 amps..!What is the voltage drop running through resistor five? 45 volts...!What is the equivalent resistance through the parallel portion of the circuit? 6 ohmsAnswerA resistor is a conductor, albeit one with a higher resistance than a length of wire, so current passes through it without any problem. The magnitude of the current will, of course, be somewhat lower because of the additional resistance.
Why do some circuits need resistors?
A circuit does need resistance but not necessarily a resistor. without any resistance a circuit will be considered a "short circuit" and you power source will most likely overheat. Resistance can be created in millions of different ways. This could be something such as an or any other light source but also a module such as a capacitor resistor or diode. To get to you're question more directly a circuit needs resistance to keep from shorting out. A specific module(such as an LED) would need a resistor to lower the voltage so to a point where the module can accept the power without burning out.
Why you cannot measure the resistance of a resistor when there is current passing through it?
you can if you know the current measure the voltage across the resistor E=I*R there is actually no way to measure the resistance without passing current thru it P=I*E E=I*R any 2 will give you the other 2
What does one-quarter W mean for a rated resistor?
It means that the resistor will safely dissipate the heat involved in transporting that much power through, without burning up/out. If you exceed that rating, the resistor will become too hot for its own good.Power is always linked with Voltage and Current, and Current is linked with Voltage and Resistance of the resistor. You will do well to remember the tandem of laws:Power [Watts] = Potential [Volts] * Current [Amperes]andCurrent [Amperes] = Potential [Volts] / Resistance [Ohms]For example, if you have a 100ohm resistor rated at 0.25W, then to satisfy that requirement, a voltage of no more than 5V can be applied to it, because 5V / 100ohm = 0.05A, and 0.05A * 5V = 0.25W.
What is the current flowing through a 200 watt resistor that has a rating of 21 ohms?
The current can't be calculated from the information given in the question.The power rating of a resistor is the maximum power it can dissipate before it overheatsand its resistance possibly changes permanently. The power rating is not the amount ofpower it always dissipates.So, all we really know about the resistor in the question is that its resistance is 21 ohms.And all we can say about the current through it is:Current through the resistor = (voltage between the ends of the resistor) divided by (21).
How is resistance calculated?
You can measure it, but you can't calculate it. That's why the resistance of a resistor is always printed on it, either in numbers or in color bands. Without that marking, the resistor is pretty useless. If it accidentally missed being marked during manufacture, it would be either discarded, or sold surplus for bubkes.
What is power and current if resistor is 500 ohm?
The question is incomplete without the voltage across the resistor. For example: if V (Voltage across 500 ohm resistor) = 5 Volts, then, Current, I = 5/500 Ampere = 0.01 A.
What is the power rating of a resistor?
The power rating of a resistor determines how much power it can dissipate without being damaged. For example, a 1/4W resistor is designed to handle up to 1/4W continuously without being destroyed. When selecting a resistor to use in a circuit, use Ohm's law to calculate the power it will dissipate. For example, placing a 1kΩ resistor across a 12VDC signal will allow 12/1000 = 0.012A to flow thru the resistor. 0.012*12 = 0.144W will be dissipated. Thus, a 1/8W (0.125W) resistor would not be sufficient, and a 1/4W (0.25W) must be used.
