Series and Parallel DC Circuits

piquantdistractedElectronics - Devices

Oct 5, 2013 (3 years and 10 months ago)

128 views

Physics 2B

1




Series & Parallel DC Circuits Resistors





Introduction:

This exercise is designed to give you experience in setting up and making
measurements on DC circuits. This will include using the multimeter, drawing and using circuit
diagrams, using a variety of power supplies and other necessary circuit elements, and
using the PROTO
-
BOARD to build DC circuits. More specifically, you will experimentally verify:




1.

The equivalent resistance equation for ohmic DC circuits involving resistors in series.

2.

The equivalent resistance equation for ohmic

DC circuits involving resistors in parallel.





Theory
:
Using your text as a reference, show complete derivations for each of the following equations:


1.

The equivalent resistance of a DC circuit that has three different resistors in series in terms of the
values of the resistances. Be sure to draw a circuit diagram that includes a DC power supply,
voltmeter (connected to measure the equivalent resistance)
, and an ammeter.


















2.

The equivalent resistance for three different resistors in parallel. Draw the corresponding circuit
diagram.


















Experiment

6

Physics 2B

2


Procedure:

1.

T
HE
C
IRCUIT
B
OARD
:

A

CONVENIENT WAY TO SE
T UP CIRCUITS IS WIT
H A
"PROTO
-
BOARD".

I
N ORDER TO
USE THIS DEVICE
,

YOU NEED TO KNOW HOW

IT IS
"
BUSED
",

WHICH IS NOT SHOWN O
N THE BOARD
.

U
SING AN
OHMMETER
,

ESTABLISH THE BUS LI
NES OF THIS BOARD
(H
OW WILL YOU DO THIS
?)

AND SHOW THEM ON THE

FIRST BOARD DIAGRAM
PROVIDED ON PAGE
4

2.


a.

C
HOOSE THREE
1/
4W

RESISTORS
.

P
LACE THEM IN SERIES
ON THE
PROTO
-
BOARD

AND MEASURE
THEIR RESISTANCES WI
TH THE MULTI
-
METER
.

b.

Y
OU WILL HOOK UP A PO
WER SUPPLY
,

AMMETER AND VOLTMETE
R
.

F
IRST

CALCULATING THE MAXI
MUM
CURRENT
.

i.

I
MAX
,

SERIES

=



c.

U
SE THIS TO DETERMINE

MAXIMUM
VOLTAGE

i.

V
MAX
,

SERIES

=




d.

H
OOK THE POWER SUPPLY

TO THE
PROTO
-
BOARD

AT A VALUE UNDER THE

MAXIMUM VOLTAGE
.

M
EASURE THE SUPPLIED
VOLTAGE
,

V
S

e.

M
EASURE THE CURRENT T
HROUGH THE RESISTORS
.

f.

M
EASURE THE POTENTIAL

DIFFERENCES ACROSS E
ACH INDIVIDUAL RESIS
TOR
.



3.

R
EPEAT PROCEDURES A
-
E ABOVE FOR THREE DI
FFERENT RESISTORS IN

PARALLEL
.

Y
OU MAY USE THE SAME
THREE RESISTORS
.


i.

I
MAX
,

PAR

=



ii.

V
MAX
,

PAR

=





Data and Results:


1.

Resistors in Series


R
1

= __________
_____ R
2

= _______________ R
3

= _______________



V
s

= _______________

I = _______________



V
R1

= _______________

V
R2

= _______________

V
R3

= _______________




a. R
eq, m

= V
s
/I = _______________ R
th

= _______________




% Error of Equivalent Resistance = ____________


b. Energy Conservation




V
R1

+ V
R2

+
V
R3

= ______________

% error (with V
s
) _______________




2.

Resistors in Parallel



R
1

= _______________ R
2

= ____________
___ R
3

= _______________




V = _______________ I = _______________


R
eq,m

= V/I =_______________ R
th

= _______________



% Error of Equivalent Resistance = ____________

Physics 2B

3


Proto
-
Board Diagrams


Diagram 1: Bus lines























Diagram 2: R
esistors in series and
parallel