... lamp (Type F, G, H, I) , 22W(A, B, C, E). Its active arm is a special design, which can be adjusted conveniently ... for long time observation, rectangle 177×113mm is a better choice because its shape change is smaller than round 127mm and can be ... lamp is under a normal working ( 22W lamp impedance is 5Ω, 12W lamp impedance is 10Ω,7W lamp impedance is 11Ω) and the plugs is in a good ...