Ncert Exercises & Solutions

If the resistance R₁ is increased (see figure), how will the readings of the ammeter and voltmeter change?

Hint:

I_{B} = \frac{V_{BB} - V_{BE}}{R_{i}}

Step 1: Find the change in base current.

Consider the circuit in fig. (b) to find the change in readings.

As we know the formula for base current,

I_{B} = \frac{V_{BB} - V_{BE}}{R_{i}}

Step 2: Find the change in the ammeter reading and the voltmeter reading.

As R_{i} is increased, I_{B} is decreased .

Now, the current in ammeter is collector current I_{C} .

I_{C} = {βI}_{B} as I_{B} decreases I_{C} also decreases and the reading of voltmeter and ammeter also decreases .