CHAPTER 4. DIODE CIRCUITS734.3.7ClippingA diode clipping circuit can be used to limit the voltage swing of a signal. Figure 4.12 showsa diode circuit that clips both the positive and negative voltage swings to references voltages.+++V1-V2R->VsSGFigure 4.12: Diode clipping circuit and its output waveform.4.3.8Diode GateDiodes can also be used to pass the higher of two voltages without aﬀecting the lower. Anifty example is shown in ﬁgure 4.13 The 12 V battery does nothing until the power fails;then it takes over without interruption.+12V to+15V+15V--+12VFigure 4.13: Diode OR gate.4.3.9Diode ProtectionAn important use of diodes is to suppress the voltage surge present when an inductive loadis switched out of a circuit – inductive surge suppression. With inductors it is not possibleto turn oﬀ the current suddenly since the inductor will try to keep the current ﬂowing whenthe switch is opened. A diode in a DC circuit or back-to-back zener diodes in an AC circuitcan be used to shunt the inductor and prevent it from conducting.