This course is designed to give students the basic notions regarding the correct management of a measurement process and the knowledge and use of instruments aimed at measuring electrical quantities. The measurement management will be described according to the international framework and to the accepted rules for the expression of uncertainty in measurements. The section related to the measurement of low frequency electrical quantities is based on teaching lessons in classroom and experimental activity in laboratory to get used to the described measurement techniques and instruments.

The expected outcomes concern knowledge of the structure and operating principles of electronic instrumentation, the ability to analyze and design signal conditioning circuits for sensors and data acquisition systems, the calculation of measurement uncertainty, and the analysis and correction of systematic errors. The student should also be able to analyze the specifications of commercial instruments and sensors and make design choices aimed at achieving the best performance from a measurement perspective. The student will therefore learn to use laboratory instrumentation consciously and to critically analyze the performance of the implemented system.

Elettrotecnica, analisi matematica

Metrology basics: • International organization. Instrument calibration and traceability. Direct and indirect measurements. Uncertainty expression and propagation. Instrument metrological characteristics. Vocabulary of metrology. Measurement instruments: • Basics on magnetoelectric instruments for DC quantities (voltmeter, current meter) based on a microammeter, transduction principle and design guide-lines. • Instrument evolution and structure of a digital instrument for electrical and non- electrical quantities. • Analogue to digital converters for measurement applications. • Digital multimeters, measurements of DC, AC quantities, 2 wires and 4 wires resistance measurements. • AC to DC converters for RMS and true RMS measurements. • High current and non-contact current measurements, current transformers, Hall sensors, current clamps. • Basics on signal sampling and signal acquisition. Digital oscilloscopes structure and working principle. Bandwidth and systematic effects in frequency and time domains. Oscilloscope probes. • Impedance measurements, power measurements, energy measurements in single phase and (basics) three phase power systems. Digital power meters. Methods • Resistance measurements: Ammeter-voltmeter method, comparison method, applications to low values (conductor resistivity measurements) and high-values (volume resistance of isolators) analysis and correction of systematic effects. • Voltage and currents sensor calibration in DC and AC conditions. • Impedance measurements, electrical power measurements. Laboratories (provisional list): • Measurement of electrical quantities in direct current (DC) • Measurement of electrical quantities in alternating current (AC) • Use of the oscilloscope • Characterization of current sensor • Power measurements

Classroom lectures: 45 hours. Laboratory exercises: 15 hours, to be carried out in small groups. Laboratory attendance is not mandatory.

- Modern measurements : fundamentals and applications (A. Ferrero, D. Petri, P. Carbone, M. Catelani), IEEE press (available online from the Politecnico website). - Electrical measurement, signal processing and displays, Edited by Johnn Webster, CRC Press

Slides; Esercizi risolti; Esercitazioni di laboratorio; Strumenti di simulazione;

E' possibile sostenere l’esame in anticipo rispetto all’acquisizione della frequenza

Modalità di esame: Prova orale obbligatoria; Elaborato scritto prodotto in gruppo;

Exam: Compulsory oral exam; Group essay;

... Oral exam (max score: 30 points) and evaluation of the laboratory reports (max score: 3 points) The oral exam usually lasts from 30 to 50 minutes, includes a discussion of the topics presented during the lectures, exercises similar to the ones described during the lessons, a discussion of the report. The laboratory report is a short report that will be written during the laboratory, or in the following days, according to a structure that will be described during the lessons. The evaluation concerns the report content and the presence to the laboratory. A single absence from the laboratory does not entail penalties. Attendance at the laboratories is not mandatory.

Gli studenti e le studentesse con disabilità o con Disturbi Specifici di Apprendimento (DSA), oltre alla segnalazione tramite procedura informatizzata, sono invitati a comunicare anche direttamente al/la docente titolare dell'insegnamento, con un preavviso non inferiore ad una settimana dall'avvio della sessione d'esame, gli strumenti compensativi concordati con l'Unità Special Needs, al fine di permettere al/la docente la declinazione più idonea in riferimento alla specifica tipologia di esame.