question_answer

Name the type of biasing which results in very high resistance of a p-n junction diode. In the given circuit, a voltmeter 'V? is connected across a bulb 'B'. What changes would occur in bulb 'B' and voltmeter 'V?, if the resistor 'R' is increased in value? Give reason for your answer.              

Answer:

                    The reverse biasing results in very high resistance across the p-n junction. If the value of the resistance R is increased, the current in the forward biased input circuit decreases. The emitter current \[{{I}_{E}}\] decreases and hence the collector current \[({{I}_{C}}={{I}_{E}}-{{I}_{B}})\] also decreases. The glowness of the bulb decreases. Due to decrease in \[{{I}_{C}}\], the potential drop across the bulb B decreases and hence the voltmeter shows a lower voltage.