Symbolic representation of a photodiode is

Take the breakdown voltage of the zener diode used in the given circuit as $6 \mathrm{V}$. For the input voltage shown in the figure below, the time variation of the output voltage is: (Graphs drawn are schematic and not to the scale)

For the circuit shown below, calculate the value of $I_{\mathrm{z}}:$

The transfer characteristic curve of a transistor, having input and output resistance $100 \mathrm{\Omega }$ and $100 \mathrm{k}\mathrm{\Omega }$ respectively, is shown in the figure. The voltage and power gain, are respectively:

An n-p-n transistor has three leads A, B and C. Connecting B and C by moist fingers, A to the positive lead of an ammeter, and C to the negative lead of the ammeter, one finds large deflection. Then, A, B and C refer respectively to :

The arrangement of $\mathrm{NAND}$ gates shown below effectively works as