EXPERIMENT7

Transistor as a switch.

1 x Small Signal NPN transistor, 2 resistors( R1=10K, R2=1K ).

Connect the multimeter between base and emitter.

Note the voltage reading and explain what this reading is indicating.

750mV. Becasue Vbe need to exceed 0.7 volts to operate and it is indicating that it is working correct.

Connect the multimeter between collector and emitter.

Note the voltage reading and explain what this reading is indicating.

52.4mV. This is indicating that the transistor is open, current flowing.

In the plot given below what are the regions indicated by the arrows A&B?

A indicates the saturation region and B indicates the cut off region.

How does a transistor work in these regions?

The saturated region means that the transistor is on and that it is a foward biased.

What is the power dissipated by the transistor at Vce of 3 volts?

Vce at 3 volts= (β= Ic /Ib) 12.5/0.5 β=25

What is the Beta of this transistor at Vce 2,3 & 4 volts?

β= Ic / Ib =

Vce 2 = 20/0.8=25

Vce 3 = 12.5/0.5=25
Vce 4 = 5/0.2=25