# Instrumentation Tecniques

## Objectives

The discipline of Instrumentation intends to develop knowledge in circuit analysis  and a overview about the different instruments used to measure quantities whose process is based in transforming the signal associated to a given quanity  into an electrical signal. In this sense, it is essential that students know how to analyze passive and active electrical circuits, in steady state and transient conditions, respectively. In addition, it is important that students know the symbols to be used.
In terms of meters, it is important that students know how the digital and analog gauges and what distinguishes them. In addition, the students should know what kind of signal transducers exist and how they interact with the quantities to be measured.
Finally it is intended to provide an overview of the measurement systems and their necessity in the vast field of Control Engineering and Testing.

## General characterization

7474

6.0

##### Responsible teacher

Rodrigo Ferrão de Paiva Martins, Rui Alberto Garção Barreira do Nascimento Igreja

##### Hours

Weekly - 5

Total - Available soon

Português

### Prerequisites

Obtain knowledge of basic mathematical analysis and Physics.

### Bibliography

- Powerpoints from theoretical classes

- Fundamentals of Electric Circuits, Charles K. Alexander, Matthew Sadiku, MacGraw-Hill, 2004

- The Art of Electronics, Paul Horowitz, Winfield Hill, Cambridge University Press 2001

- Electronic Instruments and Measurements, Larry Jones, Foster Chin, Prentice-Hall.

### Teaching method

The teaching method is based on three types of lessons: Lectures, present registered for statistical purposes and positive discrimination (recovery point value between 0.5 to 1 for those who participate in 100% or 90% of classes); evaluation proceeds from theoretical component through resolution of issues, to be held in the classroom after their exposure or as student tutorial work, a set for large area taught. Are expected 8 large sets, of which 4 are kind of inquiry answer true or false; the  problem solving session  and compulsory laboratory sessions, whose no presence determines the exclusion from final exam.

Available soon

## Subject matter

1. Basic Components and Electric Circuits

Electrical quantities and units: charge, current, voltage and power. The current direction and polarity of the voltage.  Ideal sources of voltage and current. Dependent sources. Resistance and Ohm''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''s Law.

2. Currents and Voltages Laws

Notions of nodes, branches and loops. Kirchhoff laws (KCL and KVL). Circuit analysis in series and parallel. Parallel and series combination of sources. Voltage and current  divider.

Measuring instruments. Errors in instrumentation. DC meters. Potentiometric circuit.  d''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''Arsonval meter, voltmeter, ammeter to ohmmeter, sensitivity of the measuring instruments, internal resistance and load resistance.

3. Circuit Analysis Techniques

Superposition.Thevenin and Norton theorems. Maximum power transfer.

Resistance measurements: Wheatstone bridge. Half-bridge circuits and quarter bridge. Kelvin Bridge.

4. Bipolar Transistores (BJT) - Introduction

Bipolar transistors (BJT) in DC.

5. Operational Amplifiers

The ideal model. Applications: voltage follower. Non-inverting and inverting amplifier. voltage adder.

Instrumentation Amplifier. Amplifying the signal from a Wheatstone bridge. Current-voltage converter.

6. Capacitors and Inductors
Voltage-current relation in an ideal capacitor. Current-voltage relationship in an ideal inductor. Calculation of energy stored in capacitors and inductors. Analysis of the temporal response of capacitors and inductors. Combinations of series and parallel capacitors and inductors. Time constant in RC and RL circuits.

Circuits for differentiators and integrators.

Natural and forced response of circuits. RLC circuit. The resonance frequency and damping factor in series and parallel for RLC circuit. Critical damping and sub critical damping.

7. Sinusoidal analysis

Characteristics of sinusoidal functions. Representation as phasor. Conversion between the time domain and frequency. Impedance and Admittance. Combination of series and parallel in the frequency domain. Application of techniques in the frequency domain analysis of circuits.

Use d''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''Arsonval meter for measuring AC signals. Rectifiers. AC Bridges: balancing an impedance bridge, Wien Bridge, Maxwell Bridge, Schering Bridge.

Instantaneous power, average power. Quadratic average value. Reactive power. Relationship between the complex power, average and reactive. Power factor and load.

8. Apparatus and measurement techniques
Digital multimeter, oscilloscope, electrometer, lock-in.

9. Transducers (Introduction)
Classification of transducers. Position transducers (resistive), deformation (strain), capacitive, inductive, piezoelectric, temperature, ultrasonic, photoelectric.

## Programs

Programs where the course is taught: