# Illustration Capacitor with set stopping voltage for photoelectric effect

A plate capacitor consists of two electrodes (capacitor plates). A stopping voltage $$U_{\text G}$$ is set between the electrodes.
An electrode is now irradiated with photons of the energy $$h \, f$$. The photons land on the electrode surface and eject electrons. Because of the applied stopping voltage, the electrons are decelerated (stopped) by the negatively charged capacitor plate.