| 1 | A | B | C | D |
| --- | --- | --- | --- | --- |
| 2 | Conventional electrical unit - Definition |  |  |  |
| 3 | Constant | Conventional exact value (CIPM, 1988; until 2018) | Empirical value (in SI units) (CODATA, 2014) | Exact value (SI units, 2019) |
| 4 | Josephson constant | KJ-90 = 483597.9 GHz/V | KJ = 483597.8525(30) GHz/V | KJ = 2 × 1.602176634×10−19 C/6.62607015×10−34 J⋅s |
| 5 | von Klitzing constant | RK-90 = 25812.807 Ω | RK = 25812.8074555(59) Ω | RK = 6.62607015×10−34 J⋅s/(1.602176634×10−19 C)2 |

Question: In 1988, what was the official value for the KJ-90 and the von Klitzing constants?
Answer: In 1988, the CIPM conventional values for the Josephson constant as exactly KJ-90 = 483597.9×10⁹ Hz/V and for the von Klitzing constant as exactly RK-90 = 25812.807 Ω.