Yuba is a household appliance installed in the bathroom for heating and lighting. The nameplate and simplified circuit diagram of a Yuba are as follows, where L is a photo.

According to: p = ui, I = p/u = 40w/220v ≈ 0. 182a.

2. Close s 1 and s2, and disconnect S, L 1 and L2 in parallel:

P total = 400w× 2 = 800w = 0.8kw

w = Pt = 0.8 kw×0.5h = 0.4 kw·h

3. Close three switches at the same time, and the total power is: pTotal = 400W+400W+40W = 840W.

I always = p always/u = 840 w/220 v ≈ 3.82a.

R total = u/I total = 220v/3.82a = 57.62ω.