In the figure, D1 is a real silicon pn junction diode with a drop of 0.7V under forward bias condition and D2 is a zener diode with breakdown voltage of -6.8 V. The input Vin(t) is a periodic square wave of period T, whose one period is shown in the figure.

Assuming 10 τ <<T. where τ is the time constant of the circuit, the maximum and minimum values of the output waveform are respectively.