EET 300 Lecture Notes - Lecture 4: Ohmmeter, Short Circuit, Voltmeter

• School: Old Dominion University
• Department: Electrical Engineering Technology
• Course: EET 300
• Professor: Jones

Document Summary

Suppose you have a black box with two wires sticking out of it. You have no idea what kind of electronics package is inside, but it is possible to take some basic measurements to determine how it will affect the other circuits to which it may be connected. You can connect a voltmeter to its output and measure the voltage it will apply to whatever it is hooked up to. This voltage is the open-circuit voltage (i. e. , no current) and we call it vthevenin. You can also short the outputs together and measure the short circuit current (i. e. , no voltage). You can then use the two measured values to calculate the resistance of the unknown circuit from the viewpoint of the load known as. This is not a value you can get by hooking up an ohmmeter to the output. As a matter of fact, it is rarely a good idea to short an output in real life.