Taha Ismaeel
19080333
Physics
Circuits
Unit 15: Electrical circuits and their applications
A: understand electrical symbols, units, definitions, relationships and properties of circuit
components for use in the construction of circuits.
B: Construct series and parallel circuits for use in standard electrical applications and measure
electrical values.
Section 1 – Electrical symbols, units and definitions
, Taha Ismaeel
19080333
Physics
Electrical Terms Meaning Symbol (If applicable)
Current (Ampere)
Potential Difference (Volt)
Electrical Charge (Coulomb)
Resistance (Ohm)
Conductance (Siemen)
Electrical power (Watt)
Capacitance (farad and sub units)
Conductance and resistance in
relation to density of mobile
charge carriers
Current in terms of flow of
mobile charge carriers
Electromotive force (EMF) as a
measure of ratio of energy
supplied per unit of charge
Section 2: Electrical formulae and relationships
Kirchhoff’s first law- It states that the number of currents flowing into a junction in an electrical
circuit equals the sum of currents flowing out of the junction.
Example: this is showing that I1 + I2 = I3 + I4 + I5
Using Kirchhoff’s first law we can work out this question. 2 arrows are going in (I1&I2) 3 are going
out (I3, I4 & I5) form this we know current flowing in is the same current flowing out.
So, answer I1 + I2 = I3 + I4 + I5
Kirchhoff’s second law- Kirchhoff's second law deals with voltage drops through circuit components.
It states that the direct sum of potential differences across components is zero around any closed
loop in a circuit.
Example: emf = pd1 + pd2 + pd3 + pd4=0 (Equation)
(EMF= Electro motive force)
19080333
Physics
Circuits
Unit 15: Electrical circuits and their applications
A: understand electrical symbols, units, definitions, relationships and properties of circuit
components for use in the construction of circuits.
B: Construct series and parallel circuits for use in standard electrical applications and measure
electrical values.
Section 1 – Electrical symbols, units and definitions
, Taha Ismaeel
19080333
Physics
Electrical Terms Meaning Symbol (If applicable)
Current (Ampere)
Potential Difference (Volt)
Electrical Charge (Coulomb)
Resistance (Ohm)
Conductance (Siemen)
Electrical power (Watt)
Capacitance (farad and sub units)
Conductance and resistance in
relation to density of mobile
charge carriers
Current in terms of flow of
mobile charge carriers
Electromotive force (EMF) as a
measure of ratio of energy
supplied per unit of charge
Section 2: Electrical formulae and relationships
Kirchhoff’s first law- It states that the number of currents flowing into a junction in an electrical
circuit equals the sum of currents flowing out of the junction.
Example: this is showing that I1 + I2 = I3 + I4 + I5
Using Kirchhoff’s first law we can work out this question. 2 arrows are going in (I1&I2) 3 are going
out (I3, I4 & I5) form this we know current flowing in is the same current flowing out.
So, answer I1 + I2 = I3 + I4 + I5
Kirchhoff’s second law- Kirchhoff's second law deals with voltage drops through circuit components.
It states that the direct sum of potential differences across components is zero around any closed
loop in a circuit.
Example: emf = pd1 + pd2 + pd3 + pd4=0 (Equation)
(EMF= Electro motive force)
