Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • NCERT
  • 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

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 an 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 characteristics shown in Fig. 14.18 (c) to (h), determine the arrangement of components between A, B, and C.

Answers (1)

Explanation:-

a) In this case, the voltage across the two terminals is positive, which suggests the possibility of current flowing through a forward-biased diode. If a germanium diode is present between A and B, it would conduct in the forward direction once the voltage exceeds the threshold (around 0.3V).

n-side of the PN junction is connected to the A terminals while B is connected to the top-side of PN junction.

b)  The voltage across A and B is reversed. Since a germanium diode doesn't conduct in reverse, the graph should show no current flow for this combination. The knee voltage is 0.7V.

c) The diode between B and C is in a forward-biased condition. The graph should show a characteristic diode's forward voltage drop (approximately 0.3V), and then the current should increase rapidly once the threshold is passed. C is connected to the PN junction and n-side of the junction is connected to the B terminal, and knee voltage is 0.7V.

d) Since the voltage is reversed, the diode between B and C will be reverse-biased, and no current should flow. This above condition explains the connection between pn-junction with I and II with the resistance.

Posted by

infoexpert24

View full answer

Similar Questions

Latest Question