L07_Ammeters~

L07_Ammeters~ - IUPUI PHYS 251 LAB Page 1 of 4 AMMETERS AND...

This preview shows pages 1–2. Sign up to view the full content.

IUPUI PHYS 251 LAB Page 1 of 4 Page 1 of 4 AMMETERS AND VOLTMETERS OBJECTIVE Electrical devices that measure current and potential difference are called ammeters and voltmeters , respectively. Often these devices are packed in a single “multimeter” which you have already used in lab. In this experiment you will be building your own ammeter and voltmeter using more fundamental electrical components and the skills you have learned so far in the course. THEORY The basic design criterion of all electrical meters is that they must not significantly disturb the circuit being measured, that is, they must have a negligible effect on all currents and potential differences in the circuit. E R 1 E R 1 A V R 2 R 2 FIGURE 1A FIGURE 1B In the series resistive circuit in Figure 1A, the current is being measured by an ammeter placed in series. The ammeter’s internal resistance must be much smaller than the resistances R 1 and R 2 in order to insure that the current is not affected by its measurement. In Figure 1B the potential difference across R 1 is being measured by a voltmeter. The voltmeter’s internal resistance must be much greater than R 1 in order to prevent a significant amount of current from being diverted into the voltmeter, thereby altering the potential difference. Before the advent of digital electronics, ammeters and voltmeters were constructed out

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 11/12/2009 for the course PHY 303L taught by Professor Turner during the Spring '08 term at University of Texas.

Page1 / 4

L07_Ammeters~ - IUPUI PHYS 251 LAB Page 1 of 4 AMMETERS AND...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online