Open-circuit voltage

<h2 id="example">Example</h2>
<p>Consider the circuit:
</p>

<p>If we want to find the open-circuit voltage across the 5Ω <a href="/facts/Resistor/JrsGReM6">resistor</a>, first disconnect it from the circuit:
</p>

<p>Find the equivalent resistance in loop 1 to find the current in loop 1. Use <a href="/facts/Ohm%27s_law/PjfEyTgI">Ohm’s law</a> with that current to find the <a href="/facts/Voltage_drop/zR5RmLKI">potential drop</a> across the resistance C. Note that since no current is flowing through resistor B, there is no potential drop across it, so it does not affect the open-circuit voltage.
</p><p>The open-circuit voltage is the potential drop across the resistance C, which is: 
  
    
      
        
          
            C
            
              C
              +
              A
            
          
        
         
        100
         
        
          V
          
            ∼
          
        
         
        .
      
    
    {\textstyle {\frac {C}{C+A}}\ 100\ V_{\sim }\ .}

</p><p>This is just an example. Many other ways can be used.<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a>
</p>
<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Electromotive_force/s6sNaHQL">Electromotive force</a></li>
<li><a href="/facts/Short_circuit/r09vaaeQ">Short circuit</a></li>
<li><a href="/facts/Th%C3%A9venin%27s_theorem/rwYa905x">Thevenin's Theorem</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>"Open Circuits". www.learnabout-electronics.org. Archived from the original on 2009-01-29.
 <a href="https://web.archive.org/web/20090129201243/http://learnabout-electronics.org/resistors_18.php" target="_blank">https://web.archive.org/web/20090129201243/http://learnabout-electronics.org/resistors_18.php</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>Thevenin's Theorem-One Independent Source, 11 January 2012, retrieved 2018-06-03 <a href="https://www.youtube.com/watch?v=LN7RoJ6GC9k" target="_blank">https://www.youtube.com/watch?v=LN7RoJ6GC9k</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
</ol>

Open-circuit voltage open-in-new

Open-circuit voltage