Measuring Resistance in Series & Parallel: Unknown Values

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In summary, the speaker is taking a circuits class and is trying to understand how to measure resistance in a circuit without given resistor values. They mention that to check resistance in series, the resistor values are added, and in parallel, the total resistance is the reciprocal of each resistor. They also ask for the best method to get approximation or exact values for multiple resistors in series or parallel. The expert speaker explains that when measuring a circuit, what is measured is the total impedance, and if measuring two resistors in series, the sum of their resistances is read. They also mention using additional information to find the individual resistor values. For parallel resistors, the formula R1R2/(R1+R2) is used, but
  • #1
xenocid3r
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Hello

I will be taking Circuits next semester. I am trying to work around a circuits book by myself.
Now I hope this is the right section to post it (its not homework, just a concept I have problem understanding).

I know that to check resistance in series I need to add the resistor value. and in parallel the total resistance will be the reciprocal of each resistor.

Is it possible to measure a circuit without any given resistor values.

If I am measuring the resistance of two or more resistors in series (or in parallel) what will be the best method to get approximation or exact values for whole of the resistors?

Thank you for your help.
 
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  • #2
When you measure a circuit what you are measuring is the total impedance of the circuit.

So if you measured two resistors in series what you would read would be the sum of those two resistances. You would then have to work backwards (using some additional information) if you wanted to find out the value of each individual resistor.
 
  • #3
ok I got it.

So if I have let's say 4 or 5 resistors, can be more. The resistance of each 2 resistors will be the sum of both of them.

So let's assume I measure 2 of the resistors,then I get x sum ofthese 2 resistors. let's say 2 resistorsfrom this network of resistors is the sum of 500 ohms.
I know that for series I check all of the resistors, create equations for each pair and solve for them.

But how would I measure if the resistors are in parallel. I know that the parallel resistance for 2 resistors is R1R2/(R1+R2). How would I measure the resistance of more then 2 resistors?

Thanks for the help Floid
 

1. How do I measure resistance in a series circuit with unknown values?

To measure resistance in a series circuit with unknown values, you will need a multimeter. Set the multimeter to the resistance setting and place the probes at either end of the circuit. The reading on the multimeter will be the total resistance of the circuit.

2. Can I measure resistance in a parallel circuit with unknown values?

Yes, you can measure resistance in a parallel circuit with unknown values. However, the process is slightly different. With a multimeter, you will need to measure the resistance of each individual branch and then use the formula 1/Rt = 1/R1 + 1/R2 + ... + 1/Rn to calculate the total resistance of the circuit.

3. What is the difference between measuring resistance in series and parallel circuits?

The main difference between measuring resistance in series and parallel circuits is the placement of the multimeter. In a series circuit, the multimeter is placed at the end of the circuit to measure the total resistance. In a parallel circuit, the multimeter is placed at different points in the circuit to measure the resistance of each branch.

4. What are the limitations of measuring resistance in series and parallel circuits?

One limitation of measuring resistance in series and parallel circuits is that the multimeter may have a limited range and may not be able to accurately measure very high or very low resistances. Additionally, the presence of other components in the circuit, such as capacitors or inductors, can affect the accuracy of the measurement.

5. Can I use Ohm's Law to calculate resistance in series and parallel circuits?

Yes, Ohm's Law can be used to calculate resistance in series and parallel circuits. However, it is important to note that the formula for calculating total resistance in a parallel circuit is different from the formula for a series circuit. Additionally, Ohm's Law assumes that the circuit is purely resistive and does not take into account the presence of other components that may affect the resistance measurement.

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