{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Electric Circuits 8th Edition 93

Electric Circuits 8th Edition 93 - 3.5 M easudns a nd ureni...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
circuit to which the meter is attached.In fact, any instrument used to make physical measu{ements extracts energy from the system while making measurements. The more energy extracted by the instnments, the more severcIy the measurement is disturbed, A real ammeter has an equivalent resistance Urat is not zero, and it thus effectively adds resistance to the cir- cuit itr series with the element whose current the ammeter is readins. A real \ohmeler bas an equivalenr resistance lhal is not inLinite, soit eFec- tively adds resistance to the circuit in pamllel with the element whose voltage is being read. How much these meters disturb the circuit beinA measured deDends on Lhe elteclive resistaDce of the meter. compared ;lh the resista;ce in t]le circuit. For example, using the rule of 1/10th, the eflective resistance of an ammeter should be no moie than 1/10th of the value of the smallest iesistance in the circuit to be sure that the current being measured is nearly t]le samewitl or without the ammeter. But in an analoe meter. the
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}