I began solving this question with nodal analysis, but I ran into 2 problems while solving the question:

  1. V_A has to be equal to zero to solve the question (and get R_1). I get 40V... I think that ground is affecting my battery?... Why is this?
  2. I got a negative value for R_3. Does this mean the current is in the wrong direction that I assumed?


  • 1
    \$\begingroup\$ It looks like you've labeled the polarity of the battery the wrong way around. The long bar of the battery symbol is positive. The short bar is negative. \$\endgroup\$ – thndrwrks Aug 22 '17 at 23:59
  • \$\begingroup\$ According to your diagram, the line with the earth symbol is reference 0V. \$V_A\$ is not zero. \$\endgroup\$ – Chu Aug 23 '17 at 0:01
  • \$\begingroup\$ The long line in the battery symbol is normally the positive terminal - which matches the +10V and -10V labels at the right side of the drawing. "Ground" is, by definition, Zero Volts, and the point we use as a reference when measuring voltages elsewhere in the circuit. \$\endgroup\$ – Peter Bennett Aug 23 '17 at 0:01

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.