Here is a little problem from the physical/electro-technical area. Only basic knowledge about electricity and resistance is required, like:

• The replacement resistance of two serial-connected resistances
  
  is 2 Ohm (R_replacement = R₁ + R₂, where R₁ = R₂ = 1).
• The replacement resistance of two parallel-connected resistances
  
  is ½ Ohm (1 / R_replacement = 1 / R₁ + 1 / R₂, where R₁ = R₂ = 1).

The question: What is the replacement resistance of the circuit below?

A hint : Click here!

The solution: Click here!