In figure what is the voltage needed to maintain 15V across the load resistance `R_(L) `of 2K, assuming that the series resistance R is` 200 Omega` and the zener requires a minimum current of 10mA to work satisfactorily? What is the zener rating required?

For a transistor amplifier, the collecor load resistance R_(L) = 2k ohm and the input resistance R_(i) = 1k ohm . If the current gain is 50, calculate voltage gain of the amplifier.

A resistor is connected to a battery of emf 10 V and internal resistance 0.3 Omega. What is the resistance of the resistor to be inserted in the circuit for the circuit current 1.2A?

A galvanometer of resistance G is converted into a voltmeter to measure upto V volts by connecting a resistance R_1 in series with the coil. If a resistance R_2 s connected in series with it then it can measure upto V/2 volts Find the resistance R, in terms of R_1 and R_2 required to convert it into a voltmeter that can read upto 2V volts.

A 10V zener diode along with a series resistance is connected across a 40V supply. Calculate the minimum value of the resistance required. If the maximum zener current in 50mA.

In the circuit shown in Fig.a voltage V is connected across lamp L. What changes would occur at lamp and the voltage V, if the resistance R is reduced in value?

Assume that the silicon diode in the circui shown in fig. requires a minimum current of 1mA to be above the knee point (0.7V) of its I-V characteristics. Aslo assume that the voltage across the diode is independent of current above the knee point. What is the power dissipated in the resistance R and in the diode, when a current of 5mA flows in the circuit at V_(B)=6V ?

Assume that the silicon diode in the circui shown in fig. requires a minimum current of 1mA to be above the knee point (0.7V) of its I-V characteristics. Aslo assume that the voltage across the diode is independent of current above the knee point. If R=1kOmega , what is the minimum voltage V_(B) required to keep the diode above the knee point?

A d.c. supply of 120 V is connected to a large resistance X. A voltmeter of resistance 10 k Omega placed in series in the ciruuit reads 4 V. What is the value of X?

Draw a simple circuit of a CE transistor amplifier. Explain its working. Show that the voltage gain, A_V of the amplifier is given by A_v = - ( beta_(ac) R_L )/(r_i) where beta_(Ac) is the current gain, R_L is the load resistance and r_1 is the input resistance of the transistor. What is the significance of the negative sign in the expression for the voltage gain?

A battery of emf 10 V and internal resistance 3 Omega is connected to a resistor. If the current in the circuit is 0.5 A, what is the resistance of the resistor? What is the terminal voltage of the battery when the circuit is closed?