NCERT Solutions for Class 12 Help.html Physics Part Ii Chapter 14 Semiconductor Electronics: Materials, Devices And Simple Circuits

A student wants to use two p-n junction diodes to convert alternating current into direct current. Draw the labelled circuit diagram she would use and explain how it works.

Give the truth table and circuit symbol for NAND gate.

Draw the typical input and output characteristics of an n-p-n transistor in CE configuration. Show how these characteristics can be used to determine (a) the input resistance (r_i), and (b) current amplification factor.

A p–n junction (D) shown in the figure can act as a rectifier. An alternating current source (V) is connected in the circuit.

The logic circuit shown below has the input waveforms ‘A’ and ‘B’ as shown. Pick out the correct output waveform.


output is

A working transistor with its three legs marked P, Q and R are tested using a multimeter. No conduction is found between P and Q. By connecting the common (negative) terminal of the multimeter to R and the other (positive) terminal of P or Q, some resistance is seen on the multimeter. Which of the following is true for the transistor?

• It is an n-p-n transistor with R as base

• It is a p-n-p transistor with R as collector

• It is a p-n-p transistor with R as emitter 

• It is an n-p-n transistor with R as collector

In the circuit below, A and B represent two inputs and C represents the output. The circuit represents

• NOR gate

• AND gate

• NAND gate

• OR gate

If in a p-n junction diode, a square input signal of 10V is applied as shown Then the output signal across RL will be 

For the given uniform square lamina ABCD, whose centre is O,

• 

• I_AD = 3I_EF

• I_AC = I_EF

• 

Carbon, silicon and germanium have four valence electrons each. At room temperature which one of the following statements is most appropriate?

• The number of free conduction electrons is significant in C but small in Si and Ge

• The number of free conduction electrons is negligibly small in all the three

• The number of free electrons for conduction is significant in all the three

• The number of free electrons for conduction is significant only in Si and Ge but small in C.