| Number | Name | Date | Kind |
|---|---|---|---|
| 3586915 | Urquhart | Jun 1971 | |
| 4295181 | Chang et al. | Oct 1981 | |
| 4301508 | Anderson et al. | Nov 1981 | |
| 4355361 | Riggs et al. | Oct 1982 | |
| 4368519 | Kennedy | Jan 1983 | |
| 4516213 | Gidden | May 1985 | |
| 4605842 | Losapio | Aug 1986 |
| Number | Date | Country |
|---|---|---|
| 2226083 | Dec 1973 | DEX |
| Entry |
|---|
| Electronic Engineering, vol. 53, No. 648, Simeon, A. et al., "Electronic Wattmeter with Differential Inputs", Feb. 1981, pp. 77-80, 85. |
| Siemens Review XLIV, No. 11, Kohler, H. et al., "Solid-State High-Precision kWh and kVArh Meter . . . ", Nov. 1977, pp. 508-513. |