Question

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

Answer 1

Let us redraw the circuit diagram to find the change in reading of the ammeter and voltmeter.

So, `I_BR_1 + V_(BE) = V_(BB)`

Base current, `I_B = (V_(BB) - V_(BE))/R_1`

`I_B ∝ 1/R_1`

So, R₁ is increased, I_B is decreased.

Now, the current in the ammeter is collector current I_C.

I_C = βI_B as I_B is decreased, I_C is also decreased and the reading of the voltmeter and ammeter also decreased.