Problem #$1$:

Build the circuit like in the figure below. The input signal $V_5=20Vppf=1Hz,V_6=5V,R_1=270.$ Assume that, $V_{\text{G}\text{R}\text{E}\text{E}\text{N}}=2\mathrm{.}2V,V_{\text{A}\text{M}\text{B}\text{E}\text{R}}=2\mathrm{.}4V,V_{\text{R}\text{E}\text{D}}=1\mathrm{.}7V$ for forward biased LED, and $V_{\text{Z}\text{E}\text{N}\text{E}\text{R}}=4V$ for reverse biased Zener diode.

Calculations: Sketch the expected voltage output $(0\mathrm{.}25$ pt $),$ determine numerically expected cutoff voltages $(0\mathrm{.}75$ pts $)$ on the graph.