THE LAWS OF ELECTRICAL CIRCUITS
1. PRINCIPAL OBJECTIVE: To calculate current and voltage in a series and parallel DC
Circuits.
2. AIMS:
To investigate the laws governing current and potential difference in electrical
circuits
To practise connecting electrical circuits.
3. THEORY.
The laws of electricity that can be used to analyse electrical circuits are Kirchhoff’s laws of
current and voltage. Electrical circuits consist of electrical components connected to each other
by electrical leads. The most basic components of a circuit are:
1. An Ammeter that is used to measure current flowing within the circuit.
2. A Voltmeter that is used to measure potential difference/voltage across the circuit.
3. A Resistor that is used to measure resistance within the circuit.
A circuit can have two types of connections, a series and a parallel connection. The main
purpose of this experiment is to use Kirchhoff’s voltage and current laws to find the voltage and
current at the resistors in the circuits.
Kirchhoff’s s law for current (KCL) states that; at any node in closed electrical circuit, the sum
Of electrical currents flowing into that node are equal to the sum of currents flowing out of that
node
Kirchhoff’s law for voltage (KVL) states that; the sum of the electrical voltage around any closed
Network (circuit) is zero and the sum of emfs in any closed loop is equivalent to the sum of the
potential drop in that loop. The sum of the products of the resistances of the conductors and
the currents in them in a closed loop is equal to the total emfs available in that loop.
4. RESULTS
Table 1: measurement of the current in series circuit
Error in Ammeter = 0.1/2 = ±0.05
R2 (Ω) I1 (A) I2 (A) I3 (A)
1.0 0.8±0.05 0.8 ±0.05 0.8 ±0.05
2.0 0.7 ±0.05 0.7 ±0.05 0.7±0.05
3.0 0.6 ±0.05 0.6 ±0.05 0.6 ±0.05
4. 0 0.55 ±0.05 0.55 ±0.05 0.55 ±0.05
5.0 0.5 ±0.05 0.5±0.05 0.5 ±0.05
1. PRINCIPAL OBJECTIVE: To calculate current and voltage in a series and parallel DC
Circuits.
2. AIMS:
To investigate the laws governing current and potential difference in electrical
circuits
To practise connecting electrical circuits.
3. THEORY.
The laws of electricity that can be used to analyse electrical circuits are Kirchhoff’s laws of
current and voltage. Electrical circuits consist of electrical components connected to each other
by electrical leads. The most basic components of a circuit are:
1. An Ammeter that is used to measure current flowing within the circuit.
2. A Voltmeter that is used to measure potential difference/voltage across the circuit.
3. A Resistor that is used to measure resistance within the circuit.
A circuit can have two types of connections, a series and a parallel connection. The main
purpose of this experiment is to use Kirchhoff’s voltage and current laws to find the voltage and
current at the resistors in the circuits.
Kirchhoff’s s law for current (KCL) states that; at any node in closed electrical circuit, the sum
Of electrical currents flowing into that node are equal to the sum of currents flowing out of that
node
Kirchhoff’s law for voltage (KVL) states that; the sum of the electrical voltage around any closed
Network (circuit) is zero and the sum of emfs in any closed loop is equivalent to the sum of the
potential drop in that loop. The sum of the products of the resistances of the conductors and
the currents in them in a closed loop is equal to the total emfs available in that loop.
4. RESULTS
Table 1: measurement of the current in series circuit
Error in Ammeter = 0.1/2 = ±0.05
R2 (Ω) I1 (A) I2 (A) I3 (A)
1.0 0.8±0.05 0.8 ±0.05 0.8 ±0.05
2.0 0.7 ±0.05 0.7 ±0.05 0.7±0.05
3.0 0.6 ±0.05 0.6 ±0.05 0.6 ±0.05
4. 0 0.55 ±0.05 0.55 ±0.05 0.55 ±0.05
5.0 0.5 ±0.05 0.5±0.05 0.5 ±0.05
