Help understanding open resistors.

[jaredogden]

I was reading through my circuits book for a beginning EE course and the book was going over troubleshooting open resistors for resistors in series.

I understand that no current will be measured across the resistor because the current path has been cut off. I don't understand how the full source voltage would be measured across that resistor though.

In my mind if there is no current how can there be full source voltage? Maybe I am not full understanding voltage and current? Or is there something else that can explain wha they were talking about?

Thanks in advance for any help.

 

[berkeman]

I was reading through my circuits book for a beginning EE course and the book was going over troubleshooting open resistors for resistors in series.

I understand that no current will be measured across the resistor because the current path has been cut off. I don't understand how the full source voltage would be measured across that resistor though.

In my mind if there is no current how can there be full source voltage? Maybe I am not full understanding voltage and current? Or is there something else that can explain wha they were talking about?

Thanks in advance for any help.

First, let's fix this:

no current will be measured across the resistor

You either measure the voltage across a resistor, or the current through it.

Next, the reason you can have a voltage with no current is because the resistance is infinite for an open circuit. So V=IR still works, since infinity multiplied by 0 can be a regular number.


EDIT -- just like a battery sitting on a table has an open circuit voltage across it, but no current is flowing.

 

[jaredogden]

I knew that looked wrong saying current through a resistor thanks for clearing that up.

Thanks for the example and explanation that makes perfect sense now.