S E C T I O N 6 . 2 I N D U C T O R S 261

CAPACITOR AND INDUCTOR SPECIFICATIONS There are a couple of important parame-ters that are used to specify capacitors and inductors. In the case of capacitors, the capac-itance value, working voltage, and tolerance are issues that must be considered in theirapplication. Standard capacitor values range from a few pF to about 50 mF. Capacitorslarger than 1 F are available but will not be discussed here. Table 6.1 is a list of standardcapacitor values, which are typically given in picofarads or microfarads. Although bothsmaller and larger ratings are available, the standard working voltage, or dc voltage rat-ing, is typically between 6.3 V and 500 V. Manufacturers specify this working voltagesince it is critical to keep the applied voltage below the breakdown point of the dielec-tric. Tolerance is an adjunct to the capacitance value and is usually listed as a percent-age of the nominal value. Standard tolerance values are ; 5%, ; 10%, and ; 20%.Occasionally, tolerances for single-digit pF capacitors are listed in pF. For example,5 pF ; 0.25 pF.

The two principal inductor specifications are inductance and resistance. Standard com-mercial inductances range from about 1 nH to around 100 mH. Larger inductances can, ofcourse, be custom built for a price. Table 6.2 lists the standard inductor values. The currentrating for inductors typically extends from a few dozen mAs to about 1 A. Tolerances aretypically 5% or 10% of the specified value.

TABLE 6.1 Standard capacitor values

pF pF pF pF F F F F F F F

1 10 100 1000 0.010 0.10 1.0 10 100 1000 10,000

12 120 1200 0.012 0.12 1.2 12 120 1200 12,000

1.5 15 150 1500 0.015 0.15 1.5 15 150 1500 15,000

18 180 1800 0.018 0.18 1.8 18 180 1800 18,000

2 20 200 2000 0.020 0.20 2.0 20 200 2000 20,000

22 220 2200 0.022 0.22 2.2 22 220 2200 22,000

27 270 2700 0.027 0.27 2.7 27 270 2700 27,000

3 33 330 3300 0.033 0.33 3.3 33 330 3300 33,000

4 39 390 3900 0.039 0.39 3.9 39 390 3900 39,000

5 47 470 4700 0.047 0.47 4.7 47 470 4700 47,000

6 51 510 5100 0.051 0.51 5.1 51 510 5100 51,000

7 56 560 5600 0.056 0.56 5.6 56 560 5600 56,000

8 68 680 6800 0.068 0.68 6.8 68 680 6800 68,000

9 82 820 8200 0.082 0.82 8.2 82 820 8200 82,000

TABLE 6.2 Standard inductor values

nH nH nH H H H mH mH mH

1 10 100 1.0 10 100 1.0 10 100

1.2 12 120 1.2 12 120 1.2 12

1.5 15 150 1.5 15 150 1.5 15

1.8 18 180 1.8 18 180 1.8 18

2 20 200 2.0 20 200 2.0 20

2.2 22 220 2.2 22 220 2.2 22

2.7 27 270 2.7 27 270 2.7 27

3 33 330 3.3 33 330 3.3 33

4 39 390 3.9 39 390 3.9 39

5 47 470 4.7 47 470 4.7 47

6 51 510 5.1 51 510 5.1 51

7 56 560 5.6 56 560 5.6 56

8 68 680 6.8 68 680 6.8 68

9 82 820 8.2 82 820 8.2 82

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