1. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 1 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I 15 Electronic Instrumentation and Measurements

2. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 2 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 15.1 Measurement system Sampling A/D conversion Digital computer Physical phenomenon Computer interface Sensor conditioning Signal Sensor

3. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 3 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 15.3 J thermocouple circuit

4. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 4 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 15.4 Cold-junction-compensated thermocouple circuit

5. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 5 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 15.16 Discrete op-amp instrumentation amplifier

6. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 6 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 15.18 AD625 instrumentation amplifier

7. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 7 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 15.19 Prototype low-pass filter response

8. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 8 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 15.21 Chebyshev low-pass filter frequency response

9. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 9 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 15.22 Salen and Key active filters

10. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 10 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 15.26 A digital voltage representation of an analog voltage

11. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 11 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 15.27 Tracking ADC Comparator Analog input Up Down Digital output + – Clock Up-down counter D/A

12. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 12 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 15.28 Integrating ADC

13. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 13 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 15.30 Description of the sample-and- hold process

14. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 14 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 15.31 Sampled data t 0 t 1 t 2 t 3 t 4 t n–1 t n v a (t) v SH (t) V(t) t

15. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 15 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 15.32 Data acquisition system

16. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 16 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 15.33 Multiplexed sampled data

17. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 17 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 15.41 Transfer characteristic of zero- crossing comparator + ~ – v out V S + V S – _ + v in v out V sat –V v in

18. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 18 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 15.42 Transfer characteristic of inverting comparator with offset + ~ – v out V S + V S – _ + V ref v out V sat –V v in V ref v in

19. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 19 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 15.48 Transfer characteristic of the Schmitt trigger + – v out v in R 2 R 1 +R 2 – V sat R 2 R 1 +R 2 V v in v out R 1 R 2 v – v +

20. © The McGraw-Hill Companies, Inc. 2000 McGraw-Hill 20 PRINCIPLES AND APPLICATIONS OF ELECTRICAL ENGINEERING THIRD EDITION G I O R G I O R I Z Z O N I Figure 15.61 NE555 timer