I Have the following Schematic:

Schematic of Two batteries

The book i am using ask for \$V_{BC}\$ which I found by \$V(B) - V(C) = 0V - 9V = -9V\$

The book gives the answer as 9V, is it safe to assume that since voltage is similar to pressure, we cant have negative pressure so I can take the modulus of my result and it would be equal to the 9V would this be allowed ?

  • \$\begingroup\$ Voltage is only a little similar to pressure. You need to understand what it is, including how does voltage behave with conductors, voltage sources and isolators. \$\endgroup\$
    – user76844
    Oct 17, 2016 at 17:48
  • \$\begingroup\$ Use V(final) - V(initial), in this case V(C) - V(B). It is very common to make sign mistakes when doing circuit analysis. Be careful. \$\endgroup\$
    – klamb
    Oct 17, 2016 at 17:49
  • 2
    \$\begingroup\$ @EugeneSh., then why do we call the base-emitter voltage of an BJT \$v_{be}\$ instead of \$v_{eb}\$? I've always seen the convention that \$v_{ab} = v_a - v_b\$. I think OP's book just has a typo or error in its solution. \$\endgroup\$
    – The Photon
    Oct 17, 2016 at 18:04
  • \$\begingroup\$ @ThePhoton Hm. Looks like you are right and I am too rusty at this theory... \$\endgroup\$
    – Eugene Sh.
    Oct 17, 2016 at 18:06
  • 3
    \$\begingroup\$ The convention definitely is \$V_{AB}=V_A-V_B\$, and the book is wrong. \$\endgroup\$ Oct 17, 2016 at 18:27


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Browse other questions tagged or ask your own question.