Accuracy & Precision in Electronics
- 1. Accuracy & Precision in Electronics
- 2. Accuracy versus Precision • What is more accurate: 47000 Ω, 47 kΩ, or 47.000 kΩ ? • Accuracy = how close to the true value • Accuracy is measured by the number of significant digits.
- 4. Rules for Significant Digits • The only Significant Digits are: • Non-zero digits • Zeros between two significant digits • Final or trailing zeros ONLY in the decimal portion
- 5. How many significant digits? 347 8074 890 90140 53.7 53.70 2.03 0.0012 0.00120 53000
- 6. Accuracy versus Precision • What is more precise: 13 mA, 12.9 mA, 12.87 mA, or 12.869 mA? • Precision = how close to the same repeated measurements are • Precision is measured by the place value of the last significant digit • stated as precise to the nearest whole number, tenth, hundredth, and so on • when adding values, maintain precision 4.7 V precise to the tenth of a volt, accurate to 2 significant digits + 6.2 V precise to the tenth of a volt, accurate to 2 significant digits 10.9 V precise to the tenth of a volt, accurate to 3 significant digits
- 7. What level of Precision? 347 Ω 8074 Ω 890 mA 90140 Ω 53.7 V 53.70 V 2.03 A 0.0012 A 0.00120 A 53.000 V
- 8. What level of Precision? 347 Ω to the nearest Ohm 8074 Ω to the nearest Ohm 890 mA to the nearest 10 mA 90140 Ω to the nearest 10 Ohms 53.7 V to the nearest tenth volt 53.70 V to the tenth of a volt 2.03 A to the hundredth of an Amp 0.0012 A ten thousandth of an Amp 0.00120 A ten thousandth of an Amp 53.000 V to the thousandth of a volt
- 9. Accuracy versus Precision • What is more precise: 13 mA, 12.9 mA, 12.87 mA, or 12.869 mA? • Precision = how close to the same repeated measurements are • Precision is measured by the place value of the last significant digit • stated as precise to the nearest whole number, tenth, hundredth, and so on
- 10. Engineering Notation • Using engineering notation can help you determine how many significant digits a number has. • Engineering notation is like scientific notation 21,378,000 = 2.1378 x 107 = 2.1378 E7 in scientific notation 21,378,000 = 21.378 x 106 = 21.378 E6 in engineering notation • Engineering notation exponents are always multiples of 3 72.45 x 103 9.541 x 109 2.77 x 10-3 3.82 x 10-6 3.14159 x 10-9 • Engineering notation gets rid of non-significant zeros 22,000 = 22 x 103 = 2 significant digits 0.00000370 = 3.70 x 10-6 = 3 significant digits
- 11. Metric Prefixes • Metric prefixes replace the exponents 103 = Kilo K 10-3 = milli m 106 = Mega M 10-6 = micro µ 109 = Giga G 10-9 = nano n 1012 = Tera T 10-12 = pico p 72.45 x 103 Ω = 72.45 KΩ 9.541 x 109 Ω = 9.541 GΩ 2.77 x 10-3 A = 2.77 mA 3.82 x 10-6 F = 3.82 µF 3.14159 x 10-9 F = 3.14159 nF