EXP1- The Oscilloscope

Aim of the experiment

1- To know the principles of the oscilloscope to know how to operate the oscilloscope and

how to use it.

2- To use the oscilloscope to measure the AC and DC potential differences (Voltage), period

and frequency of an electric oscillations.

3- To know how to use the oscilloscope to study the superposition of two periodic motions

(two sine signals) (Lissajous figures).

Devices and Instruments

Oscilloscope

Voltage measuring in oscilloscope

Where: Vp: maximum voltage. Vrms: effective values of voltage. T: period.

Laws of experiment

Vrms = 𝑉𝑝

√2

𝑉𝑝 = 𝐷𝐻

𝑇 = 𝐷𝑋

Where: D: Deflection coefficients. H: Vertical deflection (display height in division).

X: Horizontal spacing in division for one period.

EXP2-Determining the impedance of a capacitor and a resistor

Aim of the experiment

1- Determining the total impedance and phase shift in a series connection of a capacitor and

a resistor.

2- Determining the total impedance and phase shift in a parallel connection of a capacitor

and a resistor.

Devices and Instruments

Oscilloscope

Series connection

Parallel connection

Function generator

Laws of experiment

𝑇 =1

𝑓

𝜔 = 2𝜋𝑓

𝑋𝑐 =1

𝜔 𝑐

𝑍 = √𝑅2 + 𝑋𝑐2

𝜑 = 360 × ∆𝑡

𝑇

Where:

T: Period. f: Frequency. 𝜔: Angular frequency. 𝑋𝑐: Capacitive reactance. Z: Impedance.

R: Resistance. 𝜑: Phase shifted. ∆𝑡: Time difference.

EXP3- Ohm’s law

Aim of the experiment

1- Measuring the voltage and current on four constantan wires with different cross –

sectional areas.

2- Measuring the voltage and current on two constantan wires with different length.

3- Measuring the voltage and current on four constantan wire and on a brass wire.

4- Verifying Ohm’s law and determining the resistance.

Laws of experiment

𝑈 = 𝐼 𝑅

𝑅 =𝜌 𝑙

𝐴

Where:

U: Voltage. I: Current. R: Resistance. 𝑙: Length of wires. A: Cross sectional area.

𝜌: Specific resistance of the wire material.

Devices and Instruments

Experiment circuit

Volt and Ampere meter

Source

EXP4- Wheatstone bridge

Aim of the experiment

1- Measuring resistance using a bridge called Wheatstone bridge.

2- To determine the equivalent resistance of resistors connected in series.

3- To determine the equivalent resistance of resistors connected in parallel.

Laws of experiment

𝑅𝑥 =𝑅 𝑙1

𝑙2

𝑅𝑥𝑠 = 𝑅1 + 𝑅2 + ⋯ ⋯ ⋯ 1

𝑅𝑥𝑝 =

1

𝑅1+

1

𝑅2+ ⋯ ⋯ ⋯

Where:

𝑅𝑥: Unknown resistance. R, 𝑅1, 𝑅2: Known resistance. 𝑙1, 𝑙2: Length. 𝑅𝑥𝑠:

Series’ resistance law. 𝑅𝑥𝑝: Parallel’s resistance law.

Devices and Instruments

Experiment circuit

Source

Volt and Ampere meter

Wheatstone bridge

Resistance

Variable Resistance

EXP5- Induction by means of a variable magnetic field

Aim of the experiment

1- To determine the induction voltage in a conductor loop as a function of the change

excitation field (respectively the current) generating the magnetic field over time.

2- To determine the induction voltage in a conductor loop as a function of the area of the

loop.

3- To determine the induction voltage in a conductor loop as a function of the number of

windings of the loop.

Laws of experiment

𝑈 = −𝜇0 𝐴 𝑁1 𝑁2

𝐿 𝜕𝐼

𝜕𝑡

Where:

𝑈: Induction Voltage. 𝑁1 , 𝑁2: Numbers of turns. A: Cross sections. L: Length of

coil. 𝜇0: magnetic field constant. 𝜕𝐼

𝜕𝑡: Change over time of the field coil current I.

Devices and Instruments

Experiment circuit

Cassy Lab

Source

Ampere Box

Field coil

Stand for tubes and coils

EXP6- Coulomb’s law

Aim of the experiment

1- Measuring the force between small electrically charged balls as function of their charge if

balls are (+, +), both (-, -) or (+, -).

2- Measuring the force between charged balls as function distance between them.

3- Comparing the measured results with the theoretical values.

Devices and Instruments

Cobra3 basic unit

Newton

Electrometer amplifier

High voltage supply unit

𝐹 = 𝑘 𝑄1 𝑄2

𝑟2

where k is a constant of proportionality, called Coulomb’s constant, k = 8.99 x 109 N.m2 /C2. In

this experiment, you are going to verify the Coulomb’s law by using a Coulomb balance.

𝑄1 ,𝑄2 are the magnitude of the two-point charges, and r is the distance between their centers.

EXP7- Dielectric constant of different materials

Aim of the experiment

1- The relation charge Q and voltage U is to be measured using a plate capacitor.

2- The electric constant ε0 is to be determined from the relation under point 1.

3- The charge of a plate capacitor is to be measured as a function of the inverse of the

distance between the plates, under constant voltage.

4- The relation charge Q and voltage U is to be measured by means of plate capacitor,

between the plates of which different solid dielectric media are introduced. The

corresponding dielectric constants are determined by comparison with measurements

performed with air between the capacitor plates.

Laws of experiment

𝜀0 =𝑄 𝑑

𝐴 𝑈𝑐

𝑄 = 𝐶 𝑈0

Where:

𝑄: Charge of capacitor. A: Cross sections. d: Distance between the plates of the plate

capacitor. 𝜖0: Dielectric constant. 𝑈𝑐: Voltage. C: Capacity of capacitor

Devices and Instruments

High voltage supply unit

Universal measuring amplifier

Plate capacitor

Voltmeter

EXP8- the RLC Circuits

Aim of the experiment

Determination of the frequency performance of a

1- Series – tuned circuit for

a- Voltage resonance without damping resistor,

b- Current resonance without damping resistor,

c- Current resonance with damping resistor,

2- Parallel – tuned circuit for

a- Current resonance without parallel resistor,

b- Voltage resonance without parallel resistor,

c- Voltage resonance with parallel resistor,

Devices and Instruments

Series connection

Parallel connection

Cobra3 basic unit

Function generator

EXP9- Kirchhoff’s Rules

Aim of the experiment

1- Verifying Kirchhoff’s junction rule.

2- Verifying Kirchhoff’s loop rule.

Devices and Instruments

1- Junction rule: the sum of the currents entering any junction in a circuit must equal the

of the currents leaving that junction.

∑ 𝐼𝑖𝑛 = ∑ 𝐼𝑜𝑢𝑡

2- Loop rule: the sum of the potential differences across all elements around any closed-

circuit loop must be zero.

∑ ∆𝑉 = 0

Source

Volt and Ampere meter

Variable Resistance