1. Measuring chip: measuring range can reach more than 12 times; linearity: ± 0.2%; using models of CS5460, ADE7755, ade7751, ADE7758.
2. Single chip microcomputer memory memory: the United States has a strong anti-interference ability of single-chip microcomputer; the United States microchip, the United States mot, the Netherlands Phillips.
3. Electrolytic capacitor: 105 ℃, no less than 4000 hours, leakage current: < 3 μ a; Japanese Rubycon or NCC capacitor is used.
4. Power supply device: it can ensure long-term operation under 450V AC voltage; it uses resistance capacitance step-down or R-type transformer; it has low power consumption.
5. Varistor: diameter not less than 20mm, nominal voltage: 750V ± 10% or 820v ± 10%.
6. IC card holder: imported standard IC card holder, service life more than 100000 times.
7. Relay: 60A or 120a magnetic latching relay is selected.