Components: 1x Small Signal NPN Transistor, 2xResistors
Vs=15V, R1= 10KΩ, R2= 1KΩ
The voltage reading across the base and emitter is 794mV. This reading indicates the potential difference across the base and emitter. The Voltage across this part of the transistor is usually 0.5 - 0.7V so this reading was expected.
The voltage reading across the collector and emitter was 546mV. This result was expected because the 546mV result falls into the potential difference range for collector to emitter.
The regions below are: A= The saturated region
B= The cut-off region
In the cut-off region the Vce is very large, Ib will be zero and no collector current will flow.
In the saturated region Ib increases such that the maximum amount of collector current can flow, then Vce will be zero or close to it.
In both the cut-off and saturated regions, minimum power is dissipated in the transistor.
The power dissipated at Vce of 3V is calculated using Pd= Vce x Ic
= 3V x 12.5mV
= 37.5
The 12.5mV was obtained by tracking up from 3V Vce on the graph above and reading off the mV at the load line which in this case is 12.5mV.
The Beta of this transistor at 2,3 and 4V is: B= Ic/Ib
- 2V: = 20/0.8= 25
- 3V: = 12.5/0.5= 25
- 4V: = 5/0.2= 25
