Voltages across circuit elements

[tomrja]

Homework Statement

The voltages across two circuit elements in series is zero. Is it possible that the voltages across the individual elements are nevertheless not zero? Give an example.

Homework Equations

NA

The Attempt at a Solution

I am not really sure where to start with this problem. Any suggestions?

 

[Delphi51]

I can't give away very much because you haven't shown an attempt.
How about listing some "circuit elements"?
Could you meet the condition with two resistors and a current flowing through them? Why not? How about two ? elements?

 

[soothsayer]

From my point of view it seems that the only way two nonzero voltages could add up to a zero voltage is if both individual voltages were equal but of opposite sign for two circuit elements in series. Does this seem plausible?

 

[tomrja]

I read up a little bit on this subject and found that at resonance x_L=x_C, Ix_L=Ix_c, therefore V_L=V_c.

Thank you for your suggestions.

 

[Delphi51]

With inductors, you would be in the same position as with resistors; two voltages adding to make a larger voltage.

both individual voltages were equal but of opposite sign

Definitely on the right track here! Forget inductors, resistors, capacitors. Can you use two batteries?

 

[gneill]

Don't forget inductors and capacitors! Consider a series RLC circuit (with small R) driven by a voltage source near the resonance frequency. Think about phase relationships.