高周波回路設計などでは電力の表現に”dBm”や”watts”をよく使います。
dBmとはmW基準の絶対値表現で、0dBm=1mWです。
変換式はdBm=10log10(mW)です。
| dBm | mW | dBm | mW | dBm | mW | dBm | W |
|---|---|---|---|---|---|---|---|
| 0.0 | 1.00 | 10.0 | 10.0 | 20.0 | 100 | 30.0 | 1.00 |
| 0.1 | 1.02 | 10.1 | 10.2 | 20.1 | 102 | 30.1 | 1.02 |
| 0.2 | 1.05 | 10.2 | 10.5 | 20.2 | 105 | 30.2 | 1.05 |
| 0.3 | 1.07 | 10.3 | 10.7 | 20.3 | 107 | 30.3 | 1.07 |
| 0.4 | 1.10 | 10.4 | 11.0 | 20.4 | 110 | 30.4 | 1.10 |
| 0.5 | 1.12 | 10.5 | 11.2 | 20.5 | 112 | 30.5 | 1.12 |
| 0.6 | 1.15 | 10.6 | 11.5 | 20.6 | 115 | 30.6 | 1.15 |
| 0.7 | 1.17 | 10.7 | 11.7 | 20.7 | 117 | 30.7 | 1.17 |
| 0.8 | 1.20 | 10.8 | 12.0 | 20.8 | 120 | 30.8 | 1.20 |
| 0.9 | 1.23 | 10.9 | 12.3 | 20.9 | 123 | 30.9 | 1.23 |
| 1.0 | 1.26 | 11.0 | 12.6 | 21.0 | 126 | 31.0 | 1.26 |
| 1.1 | 1.29 | 11.1 | 12.9 | 21.1 | 129 | 31.1 | 1.29 |
| 1.2 | 1.32 | 11.2 | 13.2 | 21.2 | 132 | 31.2 | 1.32 |
| 1.3 | 1.35 | 11.3 | 13.5 | 21.3 | 135 | 31.3 | 1.35 |
| 1.4 | 1.38 | 11.4 | 13.8 | 21.4 | 138 | 31.4 | 1.38 |
| 1.5 | 1.41 | 11.5 | 14.1 | 21.5 | 141 | 31.5 | 1.41 |
| 1.6 | 1.45 | 11.6 | 14.5 | 21.6 | 145 | 31.6 | 1.45 |
| 1.7 | 1.48 | 11.7 | 14.8 | 21.7 | 148 | 31.7 | 1.48 |
| 1.8 | 1.51 | 11.8 | 15.1 | 21.8 | 151 | 31.8 | 1.51 |
| 1.9 | 1.55 | 11.9 | 15.5 | 21.9 | 155 | 31.9 | 1.55 |
| 2.0 | 1.58 | 12.0 | 15.8 | 22.0 | 158 | 32.0 | 1.58 |
| 2.1 | 1.62 | 12.1 | 16.2 | 22.1 | 162 | 32.1 | 1.62 |
| 2.2 | 1.66 | 12.2 | 16.6 | 22.2 | 166 | 32.2 | 1.66 |
| 2.3 | 1.70 | 12.3 | 17.0 | 22.3 | 170 | 32.3 | 1.70 |
| 2.4 | 1.74 | 12.4 | 17.4 | 22.4 | 174 | 32.4 | 1.74 |
| 2.5 | 1.78 | 12.5 | 17.8 | 22.5 | 178 | 32.5 | 1.78 |
| 2.6 | 1.82 | 12.6 | 18.2 | 22.6 | 182 | 32.6 | 1.82 |
| 2.7 | 1.86 | 12.7 | 18.6 | 22.7 | 186 | 32.7 | 1.86 |
| 2.8 | 1.91 | 12.8 | 19.1 | 22.8 | 191 | 32.8 | 1.91 |
| 2.9 | 1.95 | 12.9 | 19.5 | 22.9 | 195 | 32.9 | 1.95 |
| 3.0 | 2.00 | 13.0 | 20.0 | 23.0 | 200 | 33.0 | 2.00 |
| 3.1 | 2.04 | 13.1 | 20.4 | 23.1 | 204 | 33.1 | 2.04 |
| 3.2 | 2.09 | 13.2 | 20.9 | 23.2 | 209 | 33.2 | 2.09 |
| 3.3 | 2.14 | 13.3 | 21.4 | 23.3 | 214 | 33.3 | 2.14 |
| 3.4 | 2.19 | 13.4 | 21.9 | 23.4 | 219 | 33.4 | 2.19 |
| 3.5 | 2.24 | 13.5 | 22.4 | 23.5 | 224 | 33.5 | 2.24 |
| 3.6 | 2.29 | 13.6 | 22.9 | 23.6 | 229 | 33.6 | 2.29 |
| 3.7 | 2.34 | 13.7 | 23.4 | 23.7 | 234 | 33.7 | 2.34 |
| 3.8 | 2.40 | 13.8 | 24.0 | 23.8 | 240 | 33.8 | 2.40 |
| 3.9 | 2.45 | 13.9 | 24.5 | 23.9 | 245 | 33.9 | 2.45 |
| 4.0 | 2.51 | 14.0 | 25.1 | 24.0 | 251 | 34.0 | 2.51 |
| 4.1 | 2.57 | 14.1 | 25.7 | 24.1 | 257 | 34.1 | 2.57 |
| 4.2 | 2.63 | 14.2 | 26.3 | 24.2 | 263 | 34.2 | 2.63 |
| 4.3 | 2.69 | 14.3 | 26.9 | 24.3 | 269 | 34.3 | 2.69 |
| 4.4 | 2.75 | 14.4 | 27.5 | 24.4 | 275 | 34.4 | 2.75 |
| 4.5 | 2.82 | 14.5 | 28.2 | 24.5 | 282 | 34.5 | 2.82 |
| 4.6 | 2.88 | 14.6 | 28.8 | 24.6 | 288 | 34.6 | 2.88 |
| 4.7 | 2.95 | 14.7 | 29.5 | 24.7 | 295 | 34.7 | 2.95 |
| 4.8 | 3.02 | 14.8 | 30.2 | 24.8 | 302 | 34.8 | 3.02 |
| 4.9 | 3.09 | 14.9 | 30.9 | 24.9 | 309 | 34.9 | 3.09 |
| dBm | mW | dBm | mW | dBm | mW | dBm | W |
| 5.0 | 3.16 | 15.0 | 31.6 | 25.0 | 316 | 35.0 | 3.16 |
| 5.1 | 3.24 | 15.1 | 32.4 | 25.1 | 324 | 35.1 | 3.24 |
| 5.2 | 3.31 | 15.2 | 33.1 | 25.2 | 331 | 35.2 | 3.31 |
| 5.3 | 3.39 | 15.3 | 33.9 | 25.3 | 339 | 35.3 | 3.39 |
| 5.4 | 3.47 | 15.4 | 34.7 | 25.4 | 347 | 35.4 | 3.47 |
| 5.5 | 3.55 | 15.5 | 35.5 | 25.5 | 355 | 35.5 | 3.55 |
| 5.6 | 3.63 | 15.6 | 36.3 | 25.6 | 363 | 35.6 | 3.63 |
| 5.7 | 3.72 | 15.7 | 37.2 | 25.7 | 372 | 35.7 | 3.72 |
| 5.8 | 3.80 | 15.8 | 38.0 | 25.8 | 380 | 35.8 | 3.80 |
| 5.9 | 3.89 | 15.9 | 38.9 | 25.9 | 389 | 35.9 | 3.89 |
| 6.0 | 3.98 | 16.0 | 39.8 | 26.0 | 398 | 36.0 | 3.98 |
| 6.1 | 4.07 | 16.1 | 40.7 | 26.1 | 407 | 36.1 | 4.07 |
| 6.2 | 4.17 | 16.2 | 41.7 | 26.2 | 417 | 36.2 | 4.17 |
| 6.3 | 4.27 | 16.3 | 42.7 | 26.3 | 427 | 36.3 | 4.27 |
| 6.4 | 4.37 | 16.4 | 43.7 | 26.4 | 437 | 36.4 | 4.37 |
| 6.5 | 4.47 | 16.5 | 44.7 | 26.5 | 447 | 36.5 | 4.47 |
| 6.6 | 4.57 | 16.6 | 45.7 | 26.6 | 457 | 36.6 | 4.57 |
| 6.7 | 4.68 | 16.7 | 46.8 | 26.7 | 468 | 36.7 | 4.68 |
| 6.8 | 4.79 | 16.8 | 47.9 | 26.8 | 479 | 36.8 | 4.79 |
| 6.9 | 4.90 | 16.9 | 49.0 | 26.9 | 490 | 36.9 | 4.90 |
| 7.0 | 5.01 | 17.0 | 50.1 | 27.0 | 501 | 37.0 | 5.01 |
| 7.1 | 5.13 | 17.1 | 51.3 | 27.1 | 513 | 37.1 | 5.13 |
| 7.2 | 5.25 | 17.2 | 52.5 | 27.2 | 525 | 37.2 | 5.25 |
| 7.3 | 5.37 | 17.3 | 53.7 | 27.3 | 537 | 37.3 | 5.37 |
| 7.4 | 5.50 | 17.4 | 55.0 | 27.4 | 550 | 37.4 | 5.50 |
| 7.5 | 5.62 | 17.5 | 56.2 | 27.5 | 562 | 37.5 | 5.62 |
| 7.6 | 5.75 | 17.6 | 57.5 | 27.6 | 575 | 37.6 | 5.75 |
| 7.7 | 5.89 | 17.7 | 58.9 | 27.7 | 589 | 37.7 | 5.89 |
| 7.8 | 6.03 | 17.8 | 60.3 | 27.8 | 603 | 37.8 | 6.03 |
| 7.9 | 6.17 | 17.9 | 61.7 | 27.9 | 617 | 37.9 | 6.17 |
| 8.0 | 6.31 | 18.0 | 63.1 | 28.0 | 631 | 38.0 | 6.31 |
| 8.1 | 6.46 | 18.1 | 64.6 | 28.1 | 646 | 38.1 | 6.46 |
| 8.2 | 6.61 | 18.2 | 66.1 | 28.2 | 661 | 38.2 | 6.61 |
| 8.3 | 6.76 | 18.3 | 67.6 | 28.3 | 676 | 38.3 | 6.76 |
| 8.4 | 6.92 | 18.4 | 69.2 | 28.4 | 692 | 38.4 | 6.92 |
| 8.5 | 7.08 | 18.5 | 70.8 | 28.5 | 708 | 38.5 | 7.08 |
| 8.6 | 7.24 | 18.6 | 72.4 | 28.6 | 724 | 38.6 | 7.24 |
| 8.7 | 7.41 | 18.7 | 74.1 | 28.7 | 741 | 38.7 | 7.41 |
| 8.8 | 7.59 | 18.8 | 75.9 | 28.8 | 759 | 38.8 | 7.59 |
| 8.9 | 7.76 | 18.9 | 77.6 | 28.9 | 776 | 38.9 | 7.76 |
| 9.0 | 7.94 | 19.0 | 79.4 | 29.0 | 794 | 39.0 | 7.94 |
| 9.1 | 8.13 | 19.1 | 81.3 | 29.1 | 813 | 39.1 | 8.13 |
| 9.2 | 8.32 | 19.2 | 83.2 | 29.2 | 832 | 39.2 | 8.32 |
| 9.3 | 8.51 | 19.3 | 85.1 | 29.3 | 851 | 39.3 | 8.51 |
| 9.4 | 8.71 | 19.4 | 87.1 | 29.4 | 871 | 39.4 | 8.71 |
| 9.5 | 8.91 | 19.5 | 89.1 | 29.5 | 891 | 39.5 | 8.91 |
| 9.6 | 9.12 | 19.6 | 91.2 | 29.6 | 912 | 39.6 | 9.12 |
| 9.7 | 9.33 | 19.7 | 93.3 | 29.7 | 933 | 39.7 | 9.33 |
| 9.8 | 9.55 | 19.8 | 95.5 | 29.8 | 955 | 39.8 | 9.55 |
| 9.9 | 9.77 | 19.9 | 97.7 | 29.9 | 977 | 39.9 | 9.77 |