# Electricity and Electronics

**Mechanical Engineering**

5 ECTS; 1º Ano, 2º Semestre, 15,0 T + 30,0 PL + 15,0 TP + 3,50 OT

**Lecturer**

- Luís António Rodrigues de Figueiredo Ferreira Pereira

**Prerequisites**

Not applicable.

**Objectives**

Provide students with the fundamental concepts used to study alternating and direct current. Introduction to the fundamental components in electronic circuits and methods of analysis of these circuits. Study of basic circuits based on operational amplifiers, diodes, transistors and digital logic gates.

**Program**

1. DC circuits.

1.1. Constitution of matter.

1.2. Definitions; fundamental variables: electric current, voltage.

1.3. International system of units.

1.4. Types of electric current.

1.5. Resistance, resistivity, conductance and conductivity of a metallic conductor.

1.6. Measurement instruments: voltmeter, ammeter, ohmmeter.

1.7. Materials used in electricity: conductors, semiconductors and insulators.

1.8. Ohm's law.

1.9. Voltage sources and current sources.

1.10. Joule's law. Power received and supplied by a circuit element.

1.11. Kirchhoff's laws.

1.12. Association of resistors in series.

1.13. Voltage divider.

1.14. Association of resistors in parallel.

1.15. Current divider.

1.16. Analysis of simple circuits with mixed association of resistors.

1.17. Superposition theorem.

1.18. Systematic procedures for application of Kirchhoff's laws.

1.19. Source transformations.

1.20. Thévenin's theorem.

1.21. Norton's theorem.

1.22. Maximum power transfer theorem.

1.23. Wye-delta transformations.

2. Single-phase AC circuits.

2.1. Need for alternating current.

2.2. Analytic representation and vectorial representation of alternating current.

2.3. Phase shift between sinusoidal variables.

2.4. Representation of sinusoidal variables by phasors.

2.5. AC circuit elements: resistor, capacitor and inductor.

2.6. Impedance, reactance and admittance.

2.7. Active, reactive and apparent power.

2.8. Power factor.

2.9. RLC circuits.

2.10. Power factor compensation.

3. Operational Amplifier (OpAmp).

3.1. Voltages and currents at the terminals of the OpAmp.

3.2. Voltage follower.

3.3. Inverting amplifier.

3.4. Summing amplifier.

3.5. Non-inverting amplifier.

3.6. Difference amplifier.

3.7. Instrumentation amplifier.

3.8. Voltage comparator.

4. Diodes. Theory of semiconductors.

4.1. N-type and p-type semiconductors.

4.2. Junctions.

4.3. Forward bias.

4.4. Reverse bias.

4.5. Load line.

4.6. Circuits with diodes (logic gates, rectifiers, limiters).

4.7. Special-purpose diodes: zener diode (voltage regulators), Schottky diode, LED and photodiode.

5. Bipolar junction transistors (BJT).

5.1. Operation states: cut-off, active region and saturation.

5.2. Common Emitter (CE) configuration.

5.3. Bias and stabilization.

5.4. The transistor as an amplifier.

5.5. The BJT as a current source.

5.6. Main applications of transistors.

5.7. The transistor as a switch.

5.8. Phototransistor and optoelectronic isolators.

**Evaluation Methodology**

Assessment by class attendance: The evaluation by class attendance is composed by the accomplishment of 5 practical laboratory assignments throughout the classes and 5 written tests. The practical component has the minimum score of 10 points while the written component has the minimum grade of 9 points.

Assessment by exam: The evaluation by exam is composed of the score obtained in the practical laboratory work performed during the classes and a written test in any examination period. The practical component has the minimum score of 10 values while the written component has the minimum grade of 9 values.

The final mark in each evaluation is obtained by the simple arithmetic mean between the practical laboratory component and the corresponding written component.

**Bibliography**

- Albuquerque, R. (2006). *Análise de circuitos em corrente alternada*. São Paulo: Érica

- Markus, O. (2007). *Circuitos Elétricos - Corrente Contínua e Corrente Alternada*. São Paulo: Érica

- Svoboda, J. e Dorf, R. (2012). *Introdução aos circuitos elétricos (8ª edição)*. Rio de Janeiro: LTC

- Horowitz, P. e Hill , W. (2015). *The Art of Electronics*. Cambridge: Cambridge University Press

**Method of interaction**

The course content is taught in lectures. Exercises are solved in tutorial classes. Laboratory classes are used to make and test circuits that show the application of concepts studied in the lectures and tutorials.

**Software used in class**

Multisim is recommended.