SERIES AND PARALLEL DC CIRCUIT ( LAB EXPERIMENT )
Experiment
a- Series DC Circuit
Objective
The objective of this experiment is to exam in the basic DC circuit series with the resistor
Apparatus
DC power supply
Digital multimeter
Registers
Theory overview
The series circuit is defined by a single loop in which all components are arranged inside to side manner. The key element is Kirchhoff’s voltage law with states that sum of voltage must be equal to the sum of voltage drop.
Derivation for formula
Vs = IR
V is voltage
R is resistance
I is current
Vs = IR1+ IR2 +IR3
IR t = I ( R1+ R2 + R3 )
Rt = R1+ R2 + R3
Diagrams
Procedure
1.Firstly we will find value of resistance of resistor R1,R2,R3
2.Next point equivalent resistance are the total dc series by using a R total
3.Then calculate value with the help of digital multimeter.
4.Finally value of both multimeter and calculated value with formula will be equal
Calculations
| RESISTOR | RESISTANCE |
| R1 | 21930OHM |
| R2 | 980 OHM |
| R3 | 978 OHM |
Rt = R1+R2+R3
Rt = 21930+ 980 + 978
Rt = 23888 ohm
DMM reading is 23.02kiloohm
= 23020 ohm
Result
The resistance value operated on DMM matches the value calculated by the resistor color code technique.
b- Parallel DC circuit
Objective
The objective of this experiment is to examine the basic parallel DC circuit with resistor
Apparatus
DC power supply
Digital multimeter
Resistors
Theory overview
The key element is kirchoffs current law
Which states that the sum of current in parallel DC circuit voltage is same across components and will be equal to applied source voltage.
Derivation
I=I1+I2+I3
Vs/Rt = Vs/R1 + Vs/R2 + Vs/ R3
Vs /Rt = Vs ( 1/R1 + 1 /R2 + 1/R3 )
1/Rt = R2 R3+ R1 R3 + R2 R1/ R1 R2 R3
Rt = R1 R2 R3/ R1 R3 + R2 R3 + R3 R2
Diagram
Procedure
Firstly find the value of resistance of the resistor by using digital multimeter.
Next we will measure equivalent resistance or total resistance Rt parallel to dc circuit.
Then find the total resistance with digital multimeter and check that the values equal to parallel DC circuit calculated
Observation and calculations
| RESISTOR | RESISTANCE |
| R1 | 21930OHM |
| R2 | 980 OHM |
| R3 | 978 OHM |
Rt = 958440 + 21447540+ 21491400
Rt = 2108587200/43894380
Rt = 478.8 ohm
digital multimeter value is 470.1 ohm
Result
the value of the distance measured by DMM approximately equals to the value of Rt calculated by formula.
