ENGINEERING-12L
Series-Parallel Circuits
Lab-04
Lab Data Sheet – ENGR-12L
Lab Logistics
Experimenter:
Recorder:
Date:
Equipment Used (maker, model, and serial no. if available)
Directions
1. Check out a Fluke DMM (for volts and ohms) and a Scope 360 DMM (for current)
2. Go to the side counter, collect resistors, “bread board”, and leads required to construct the
circuit shown in Figure 1.
3. Make the DMM-Measurements1 and Calculations needed to complete Table III
 Measure RT, the total circuit resistance, by removing the power supply, and applying the
ohmmeter probes across the input & output circuit connections.
 Calculate RT using two different methods
o By the Series-Parallel calculation from the individually measured resistances
o By V/I using the measured values of Current & Voltage
 The experimenter must determine WHICH I & V to use in this calculation
4. Return all lab hardware to the “as-found” condition
1
CAREFULLY Select the DMM range such that meter displays at least FOUR (4) digits. All DMM measurements
should be reported to 4 significant figures
Adapted with permission from material produced by Bruce Mayer, PE • Chabot College • Lab4.doc • Page 1
NOTE
The Ammeter MUST be connected in series with NO potential across it; i.e.,
do NOT connect the ammeter ACROSS Vs or any R. Use the SCOPE 360
Meter to measure current since it can measure to microAmp resolution.
Figure 1 • Series-Parallel Circuit.
- Vs = 10.00 Vdc.
- R1 = 0.8-4 kΩ = R2 = 0.8-4kΩ = R3 = 0.8-4 kΩ. R4 = 1.2-9 kΩ.
- R1, R2, R3 to have the SAME nominal (color-coded) value.
- The R1,2,3:R4 Resistance RATIO to be in the range of 1.5-6
Table I DMM Values
Individual DMM measured R1-R4, assembled DMM measured RT ,
DMM measured Vs
R1 =
R2 =
R3 =
R4 =
RT=
Vs=
Table II Calculations from DMM Values
RT = R4 ||(R2 R3)=
VR1 (volt divider of Vs)
VR4 (volt divider of Vs)
VR2(volt divider of VR4)
VR3(volt divider of VR4)
I1 (Vs/RT DMM)
I23 (current div of I1)
I4 (current div of I1)
Adapted with permission from material produced by Bruce Mayer, PE • Chabot College • Lab4.doc • Page 2
Table III – Full Circuit Characterization
Value Determination
RT (note1)
RT (note2)
VR1
VR2
VR3
VR4
I1
I23
I4
Calculated
Measured
%



Note1: RT calculated by Series-Parallel combination using the Actual Values for resistors R1-R4 as determined by OhmMeter
measurement (First item in Table II). RT measured by DMM on assembled resistor network (5th item inTable I)
Note2: RT calculated from “in-circuit” Resistor measurements of Vmeas/Imeas. RT measured using I1 & Vs measurements of circuit
% calculation
 % = 100x(Valuecalc – Valuemeas)/Valuemeas
Run Notes/Comments
Adapted with permission from material produced by Bruce Mayer, PE • Chabot College • Lab4.doc • Page 3