Teaches what accuracy & precision are and how to use significant digits 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.

3. Accuracy versus Precision

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