For given circuit, the potential difference $V_{\mathrm{AB}}$ is,

Refer to the circuit given below. The output voltage $V_0$ is measured between points $a$ and $b$. Then,

Two identical $p\text{-}n$ junctions may be connected in series with a battery in three ways (figure below). The potential drops across the two $p\text{-}n$ junctions are equal in,