Q. 145.0( 2 Votes )
What happens during regulation action of a Zener diode?
A. The current in and voltage across the Zenor remains fixed.
B. The current through the series Resistance (Rs) changes.
C. The Zener resistance is constant.
D. The resistance offered by the Zener changes.
When a Zener diode is revers biased, it acts like a voltage regulator as in the breakdown region Zener diode has constant voltage for a large change in current. When an unregulated voltage is applied across the circuit shown, the Zener diode provides a constant voltage drop across it. During regulation, the current changes through the series resistance R that, leads to a change in the Zener diode resistance. This leads to a constant voltage output across its terminals and the voltage is regulated.
Rate this question :
(a) 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.
(b) Give the truth table and circuit symbol for NAND gate.Physics - Board Papers
(i) Explain with the help of a diagram the formation of depletion region and barrier potential in a pn junction.
(ii) Draw the circuit diagram of a half wave rectifier and explain its working.Physics - Board Papers
Write the two processes that take place in the formation of a p-n junction. Explain with the help of a diagram, the formation of depletion region and barrier potential in a p-n junction.Physics - Board Papers
Name the junction diode whose I-V characteristics are drawn below:
Physics - Board Papers
Using a suitable combination from a NOR, an OR and a NOT gate, draw circuits to obtain the truth tables given below:
Physics - Exemplar
What do the terms ‘depletion region’ and ‘barrier potential’ mean for a p-n junction?Physics - Exemplar
Consider a box with three terminals on top of it as shown in Fig.14.18 (a):
Three components namely, two germanium diodes and one resistor are connected across these three terminals in some arrangement.
A student performs an experiment in which any two of these three terminals are connected in the circuit shown in Fig. 14.18 (b).
The student obtains graphs of current-voltage characteristics for unknown combination of components between the two terminals connected in the circuit.
The graphs are
(i) when A is positive and B is negative
(ii) when A is negative and B is positive
(iii) When B is negative and C is positive
(iv) When B is positive and C is negative
(v) When A is positive and C is negative
(vi) When A is negative and C is positive
From these graphs of current – voltage characteristic shown in Fig. 14.18 (c) to (h), determine the arrangement of components between A, B and C.
Physics - Exemplar