Talk:Voltage drop

message: My electrician scoffed at me when I measured voltage drop on a 15 amp circuit (14 awg wire, 100 ft long) using a hairdryer as mentioned in this article.  Are there any expert sources that can confirm this as a reliable measure of voltage drop? —The preceding unsigned comment was added by Cynoscion (talk • contribs) 16:30, 13 December 2006 (UTC)
thread_title:  Measurement of Voltage drop 

message: Present Text Unclear: "A current flowing through the non-zero resistance of a practical conductor necessarily produces a voltage across that conductor." I always thought that voltage is produced by the DC supply, and that the supplied voltage generates the current. In addition, such a "practical conductor" is a passive element of the circuit, and thus produces neither voltage nor current. I propose that the first paragraph be incorporated into the second paragraph, which would be restated as follows into three new paragraphs:
Consider a circuit with a nine-volt DC source; three resistors of 67 ohms, 100 ohms, and 470 ohms; and a light bulb--all connected in series. The DC source, the conductors (wires), the resistors, and the light bulb (the load) all have resistance; all dissipate supplied energy to some degree. Their physical characteristics determine how much energy. For example, the DC resistance of a conductor depends upon the conductor's length, cross-sectional area, type of material, and temperature. 
If you measure the voltage between the DC source and the first resistor (67 ohms), you will measure slightly less than nine volts. The current passes through the conductor (wire) from the DC source to the first resistor; as this occurs, some of the supplied energy is "lost" (unavailable to the load), due to the resistance of the conductor. Voltage drop exists in both the supply and return wires of a circuit. If you measure the voltage across each resistor, you will measure a significant number. That represents the energy dissipated by the resistor. The larger the resistor, the more energy dissipated by that resistor, and the bigger the voltage drop across that resistor.
You can use Ohm's Law to verify voltage drop. In a DC circuit, voltage equals current multiplied by resistance. E = IR. Also, Kirchhoff's circuit laws state that in any circuit, the sum of the voltage drops across each component of the circuit is equal to the supply voltage. --ThatAMan (talk) 22:20, 19 August 2012 (UTC)
thread_title:  Voltage Drop in DC circuit 

message: It is, to me, entirely unclear what the point of the unlabelled, unexplained, unprofessional and hardly referenced drawing in the article is. I believe it is more confusing than helpful.  —Preceding unsigned comment added by 82.113.106.16 (talk) 02:00, 6 March 2008 (UTC)
replies: text: I thought the diagram was wonderfully colourful, but I'm inclined to agree that I can't work out what the purpose of it is.  What's really needed is a simple example  "a 10-metre length of 2.5 mm2 carrying 15 amps at 12 volts will drop XYZ".  —Sladen (talk) 22:21, 3 March 2009 (UTC)

text: The diagram IS informative, and in it's current form is certainly more beneficial than confusing.  I am inclined to agree with the above comments that it isn't really in keeping with wikipedia style, and really needs to be re-made in some diagam producing package as an SVG image. 87.194.84.113 (talk) 10:35, 8 February 2010 (UTC)
thread_title:  Drawing/Graphic 

message: Proposed new first paragraph: Voltage drop describes how the supplied energy of a voltage source is reduced as electric current moves through the passive elements (elements that do not supply voltage) of an electrical circuit. Voltage drops across internal resistances of the source, across conductors, across contacts, and across connectors are undesired; supplied energy is lost (dissipated). Voltage drops across loads and across other active circuit elements are desired; supplied energy performs useful work. Recall that voltage represents energy per unit charge. --ThatAMan (talk) 22:42, 19 August 2012 (UTC)
thread_title:  What is "voltage drop"? 

message: Since Light-emitting_diode#Colors_and_materials links to this article it should mention voltage drop across semiconductor junctions, eg in LEDs, since it is near constant rather than proportional to current as in a resistive element ? - Rod57 (talk) 18:05, 29 October 2016 (UTC)
thread_title:  Should mention voltage drop across semiconductor junctions eg in LEDs