Give the construction and working of standard hydrogen electrode with neat diagram?

Standard hydrogen electrode (SHE) is a reference electrode and its reduction potential is zero volt. By using SHE we can measure the potential of single electrodes

H₂ gas absorbed on platinum at 1 atm pressure placed in contact with 1 M HCl solution is treated as SHE. Hydrogen electrode is represented as
$\mathrm{Pt},{\mathrm{H}}_{2\left(\mathrm{g}\right)}\left(1\mathrm{atm}\right)/{\mathrm{H}}^{+}(\mathrm{C}=1)$