# Kuphaldt's Lessons In Electric Circuits, DC PDF

By Kuphaldt

Get Marie Curie and the science of radioactivity PDF

Examines the lifetime of the Polish-born scientist who, together with her husband Pierre, was once presented a 1903 Nobel Prize for locating radium.

At the present time, radar in a single shape or one other is probably going to show up in every single place: on the street, on the waterfront, in an underground motor-road. by way of a long way the widest use of radar is made by means of the army and scientists. In all of those fields hundreds of thousands upon millions of radar units are at paintings. a few of them are sufficiently small to be geared up into spectacles, others weigh hundreds of thousands of plenty.

Extra resources for Lessons In Electric Circuits, DC

Example text

Just as in the case of the diesel tractor engine and the motorcycle engine, a circuit with high voltage and low current may be dissipating the same amount of power as a circuit with low voltage and high current. Neither the amount of voltage alone nor the amount of current alone indicates the amount of power in an electric circuit. In an open circuit, where voltage is present between the terminals of the source and there is zero current, there is zero power dissipated, no matter how great that voltage may be.

For this reason we can regard the resistance of many circuit components as a constant, with voltage and current being directly related to each other. For instance, our previous circuit example with the 3 Ω lamp, we calculated current through the circuit by dividing voltage by resistance (I=E/R). With an 18 volt battery, our circuit current was 6 amps. Doubling the battery voltage to 36 volts resulted in a doubled current of 12 amps. All of this makes sense, of course, so long as the lamp continues to provide exactly the same amount of friction (resistance) to the flow of electrons through it: 3 Ω.

You will find conventional flow notation followed by most electrical engineers, and illustrated in most engineering textbooks. Electron flow is most often seen in introductory textbooks (this one included) and in the writings of professional scientists, especially solid-state physicists who are concerned with the actual motion of electrons in substances. 7. CONVENTIONAL VERSUS ELECTRON FLOW 29 sense that certain groups of people have found it advantageous to envision electric current motion in certain ways.