6
\$\begingroup\$

I'm having trouble analysing this circuit and was hoping someone could help me. The circuit in question is below.

enter image description here

I want to find the voltage drop and current across each of the parts. So far I've found the thevenin equivalent:

enter image description here

I'm a little confused as to how to find the current. Would I simply use $$\frac{11.2V}{13.33k\Omega}?$$

Or does the diode subtract 0.6 or so volts from the total voltage to be $$\frac{10.6V}{13.33k\Omega}?$$

\$\endgroup\$
  • \$\begingroup\$ The second is correct \$\endgroup\$ – Simus994 May 2 '17 at 20:42
  • 3
    \$\begingroup\$ And the next step would be to verify this current will actually make the diode into a region where it has the forward voltage drop you have assumed. \$\endgroup\$ – Eugene Sh. May 2 '17 at 20:44
18
\$\begingroup\$

Follow the arrows below. The first transition is due to making a Thevenin equivalent out of \$V_1\$, \$R_1\$, and \$R_2\$. The second transition is just summing the remaining two resistors:

schematic

simulate this circuit – Schematic created using CircuitLab

There will therefore be about \$600\:\textrm{mV}\$ subtracted away from the Thevenin voltage, leaving \$5\:\textrm{V}\$ across the total resistance of \$10\:\textrm{k}\Omega\$. About \$500\:\mu\textrm{A}\$.

\$\endgroup\$
  • \$\begingroup\$ Comments are not for extended or off-topic discussion; this conversation has been moved to chat. \$\endgroup\$ – Dave Tweed May 2 '17 at 22:07

Your Answer

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

Not the answer you're looking for? Browse other questions tagged or ask your own question.