ENGINEERING-43
Lab-02
Lab Data Sheet
– ENGR-43 Lab-02
Experimenter:
Recorder:
Date:
Equipment Used (maker, model, and serial no. if available)
Part-1 Directions
– Voltage Dividers
1. Note that in this and ALL OTHER Laboratory Exercises ENGINEERING UNITS must accompany ALL Data-Entries and Calculated-Quantities
2. Check out a DMM and Red/Black measurement Leads.
3. Go to the side counter collect resistors, “bread board”, and leads required to construct the circuit shown in Figure 1.
4. Make the DMM-Measurements 1 and Calculations needed to complete Table I

Choose Resistors within these ranges: o R1 = 2.5-4.1 kΩ o R2 = 3.7-6 k
Ω o R1:R2 ratio

1:1.5

Be sure to measure and record the ACTUAL resistor values. o NO resistor to be LESS THAN 470 Ω
1 CAREFULLY Select the DMM range such that meter displays at least THREE (3) digits, and FOUR digits if possible. All DMM measurements should be reported to MAXIMUM POSSIBLE number of significant figures.
© Bruce Mayer, PE • Chabot College • 726889163 • Page 1

Figure 1
• Voltage Divider.
V s
= 9.00 Vdc. R1 nom
= 3.3 kΩ.
R2 nom
= 4.7 kΩ.
Table I – Voltage Divider V/I Measurements and Calculations

COLOR-CODED Resistor Values & Tolerances
R1 =
R2 =

Actual (DMM) Resistor & Voltage Values
R1 =
R2 =
V
S
=
Value Determination I
L
V
R1
Calculated
Measured
Δ%
V
R2

Calculate the current and voltages using the ACTUAL values for R1, R2, and V
S
as measured with the DMM
 Calculate the Δ% for the measured value as compared to the calculated from theory for an arbitrary quantity, Q, as
© Bruce Mayer, PE • Chabot College • 726889163 • Page 2


% Q

Q calc

Q meas
Q meas
Part-2 Directions
5. Modify the previous circuit to the configuration shown in Figure 2.
6. Make the Measurements and Calculations needed to complete Table II

Choose Resistors within these ranges: o R1 = 0.5-1.6 k
Ω o R2 = 1.7-3.1 k
Ω o R3 = 4.6-6.9 k Ω o R1:R2:R3 ratio

1:2.5:5.5

Be sure to measure the
ACTUAL resistor values with the DMM. o NO resistor to be
LESS THAN
470 Ω
Figure 2 • Voltage “Trivider”. Vs = 10.00 Vdc.
R1 nom
= 1 kΩ. R2 nom
= 2.4 kΩ. R3 nom
= 5.6 kΩ.
Table II – Voltage “Trivider” V/I Measurements and Calculations

COLOR-CODED Resistor Values & Tolerances
R1 =
R2 =
R2 =
© Bruce Mayer, PE • Chabot College • 726889163 • Page 3


Actual (DMM) Resistor and Voltage Values
R1 =
R2 =
R3=
V
S
=
Value Determination I
L
V
R1
Calculated
Measured
Δ%
V
R2
V
R3
Part-3 Directions
7. Modify the previous circuit to the configuration shown in Figure 3.
8. Make the Measurements and Calculations needed to complete Table III

Choose Resistors within these ranges: o R1= R2 = R3 = 1.1-2.9 k
Ω
 ALL resistors to have the SAME nominal (color-coded) values

Be sure to measure the ACTUAL resistor values. If there is an insufficient number of the
1.1-
2.9 kΩ resistors, then choose from the lab supply resistors near the values shown. o NO resistor to be LESS THAN 470
Ω
9. Measure Va, Vb, and Vc relative to GND; i.e., for voltage measurements, connect the DMM black-lead to the OUTput of R3.

To create a SHORT circuit bridge the resistor posts with one of the bread-board interconnect wires. o This creates a Low resistance path (a.k.a. “short circuit”) around the resistor o After
“shorting” the Resistor, Measure Va, Vb, or Vc at the INPUT post to the
Resistor.

When Creating an OPEN circuit remove the wire from the INPUT to the Resistor o In This Case the NEG (black) wire from the Voltage Supply will NEVER be removed.
 i.e., at least part of the circuit will ALWAYS be grounded o After removing the input wire to the Resistor, Measure V a
, V b
, or V c
at the INPUT post FROM WHICH YOU JUST REMOVED THE WIRE.
10. Return all lab hardware to the “as-found” condition
© Bruce Mayer, PE • Chabot College • 726889163 • Page 4

Figure 3 • Open & Short Test-Circuit. V s
= 12.00 Vdc. R1 = R2 = R3 = 1.1-2.9 k Ω (2 kΩ nominal).
© Bruce Mayer, PE • Chabot College • 726889163 • Page 5

Table III – Open & Short Matrix

COLOR-CODED Resistor Values & Tolerances
R1 =
R2 =
R2 =

Actual Resistor and Voltage Values
R1 =
R2 =
R3 =
VS =
V meas
Normal R1 SC
Measured Voltage at Test Condition
R2 SC R3 SC R1 OC
V a-GND
V b-GND
V c-GND
V
R1
V
R2
V
R3 n/a

SC = S hort C ircuit o Bridge Resistor with a wire

OC = O pen C ircuit o Disconnect the wire from the INPUT side of the resistor
© Bruce Mayer, PE • Chabot College • 726889163 • Page 6
R2 OC n/a
R3 OC n/a

© Bruce Mayer, PE • Chabot College • 726889163 • Page 7
Print Date/Time = 13-Apr-20/00:15