Both the diodes used in the circuit shown are assumed to be ideal and have negligible resistance when these are forward biased. Built in potential in each diode is $$0.7V$$. For the input voltages shown in the figure, the voltage (in Volts) at point A is ___________.

Assume the left diode is forward-biased and the right diode is reverse-biased: $$V_A = V_{\text{in}} - V_{\text{barrier}} = 12.7 - 0.7 = 12\text{ V}$$

Check biasing state of the right diode: $$\text{Anode potential} = 4\text{ V}$$

$$\text{Cathode potential } (V_A) = 12\text{ V}$$

$$V_{\text{anode}} < V_{\text{cathode}} \implies \text{Reverse-biased (Open circuit)}$$

The initial assumption is consistent.