To verify power Ohm's law; to expand voltmeter range as additional resistance; to determine the unknown resistance; to regulate the desired current; for measuring the power of force and internal resistance, etc.for secondary schools,college and vocational schools

Technical parameters
1 Accuracy: class 1.
2 adjustable resistance range: 0 ~ 9999.9Ω, the minimum step value is 0.1Ω.
3 Temperature: 0 ~ 40 °C.
4 Relative Humidity: 25% to 80%.
5 Zero Resistance: Ro <0.035Ω.
6 Reference Power: 0.5W; rated power: 1W.
7 size: 165 × 125 × 60.
8 circuit between the metal parts of the shell insulation resistance> 500MΩ