Transistorused inCE amplifiercircuit whensignal of30mV isadded tothe base emitter voltage,thebasecurrent changesby 30microA andcollectorcurrent by3mA.theload resistor is 5Kohms.calculateinputresistor?

To calculate the input resistor in a common emitter (CE) amplifier circuit, we can use the formula:

Rin = ΔVbe / ΔIb

Where:
Rin = Input resistor
ΔVbe = Change in base-emitter voltage
ΔIb = Change in base current

Given:
ΔVbe = 30mV = 0.03V
ΔIb = 30μA = 0.03mA

Now, we can calculate the input resistor:

Rin = 0.03V / 0.03mA
Rin = 1000 ohms

Therefore, the input resistor in the CE amplifier circuit is 1000 ohms.

Given:

- Signal added to base-emitter voltage: 30 mV
- Change in base current: 30 μA
- Change in collector current: 3 mA
- Load resistor: 5 kΩ

To find:

- Input resistor

Solution:

1. Calculate the transconductance (gm) of the transistor:

```
gm = ΔIc / ΔVb
gm = (3 mA) / (30 mV) = 100 μS
```

2. Calculate the input resistance (Ri):

```
Ri = Vb / Ib
Ri = (30 mV) / (30 μA) = 1 kΩ
```

Therefore, the input resistor is 1 kΩ.