The range of possible load current

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Direction: In the voltage regulator circuit shown below. The zener diode current is to be limited to the range 5 ≤ i _Z ≤ 100 mA.

The range of possible load current—

1. 5 < i_L < 130 mA
2. 25 ≤ i_L ≤ 120 mA
3. 10 ≤ i_L ≤ 110 mA
4. None of these

Correct Option: B

From figure,

I =		6.3 – V_z	=	6.3 – 4.8
		12Ω		12

=	1.5 V	= 125 mA
	12 kΩ

The range of I_L: when, I_z = 5 mA
I_L = I – I_z = 125 – 5 = 120 mA
and range, when, I_z = 100 mA
I_L = 125 – 100 = 25 mA
Hence the range of I_L is 25 mA ≤ I_L ≤ 120 mA