PASCO EM-8656 AC_DC ELECTRONICS LABORATORY - Manual (Page 120)

116
AC/DC Electronics Laboratory 012-05892A
®
Exp 3- Ohm's Law
Procedure
➁-➅
)Warn the students to be particularly careful when
setting up the multimeter to measure current. Attach-
ing an ammeter the wrong way can damage the meter.
Data Processing
Resistance Current Voltage V/R % difference
100 0.02 1.579 0.02 -1.87%
560 0.00 1.582 0.00 -2.73%
330 0.00 1.582 0.00 -3.32%
1000 0.00 1.583 0.00 -9.17%
10 0.14 1.549 0.15 -13.31%
Discussion
➀
Current is inversely proportional to R
➁
Yes. A curve fit of the graph above gives Current =
1.36 x Resistance
-0.98
, which is quite close to the theo-
retical equation.
➂
) The greatest source of error is caused by the meter it-
self. Because the ammeter has some internal resis-
tance, the measured current is less than the current
when the meter is not there.
Exp 4- Resistances in Circuits
Procedure
➀-➃
Colors coded measured % error tolerance
#1 brown-black-brown-gold 100 98.9 -1.10% ±0.05%
#2 brown-black-brown-gold 100 99.6 -0.40% ±0.05%
#3 brown-black-brown-gold 100 99.7 -0.30% ±0.05%
➄ Series
R
12
= 198.3
Ω
R
23
= 199.1
Ω
R
123
= 298
Ω
➅
Parallel
R
12
= 49.7
Ω
R
23
= 49.9
Ω
R
123
= 33.3
Ω
R
13
= 49.8
Ω
➆
Combination
R
1
= 98.9
Ω
R
23
= 49.9
Ω
R
123
= 148.7
Ω
⑧
Series
R
AB
= 428
Ω
R
BC
= 891
Ω
R
ABC
= 989
Ω
Parallel
R
AB
= 76.1
Ω
R
BC
= 207
Ω
R
ABC
= 67.0
Ω
R
AC
= 84.1
Ω
Combination
R
A
= 98.9
Ω
R
BC
= 207
Ω
R
ABC
= 306
Ω