This bar graph driver circuit takes an audio input signal and displays the amplitude as a moving bar of lights. The stronger the amplitude of the signal, the more LEDs energize in the bar graph display. Predict how the operation of this circuit will be affected as a result of the following faults. Consider each fault independently (i.e. one at a time, no multiple faults):

Resistor R4 failed open:

Solder bridge (short) past resistor R3:

Resistor R11 failed open:

Zener diode D1 failed shorted:

Schottky diode D2 failed shorted: