Transistor as switch in ce and transitor as an amplifier
In the diode tutorials we saw that simple diodes are made up from two pieces of semiconductor material to form a simple pn-junction and we also learnt about their properties and characteristics.
If we now join together two individual signal diodes back-to-back, this will give us two PN-junctions connected together in series that share a common P or N terminal. The fusion of these two diodes produces a three layer, two junction, three terminal device forming the basis of a Bipolar Junction Transistor, or BJTfor short.
Transistors are three terminal active devices made from different semiconductor materials that can act as either an insulator or a conductor by the application of a small signal voltage. The transistor’s ability to change between these two states enables it to have two basic functions: “switching” (digital electronics) or “amplification” (analogue electronics). Then bipolar transistors have the ability to operate within three different regions:
- Active Region – the transistor operates as an amplifier and Ic = β*Ib
- Saturation – the transistor is “Fully-ON” operating as a switch and Ic = I(saturation)
- Cut-off – the transistor is “Fully-OFF” operating as a switch and Ic = 0
The Common Emitter Amplifier circuit has a resistor in its Collector circuit. The current flowing through this resistor produces the voltage output of the amplifier. ... The Base of the transistorused in a common emitter amplifier is biased using two resistors as a potential divider network.
In the diode tutorials we saw that simple diodes are made up from two pieces of semiconductor material to form a simple pn-junction and we also learnt about their properties and characteristics.
If we now join together two individual signal diodes back-to-back, this will give us two PN-junctions connected together in series that share a common P or N terminal. The fusion of these two diodes produces a three layer, two junction, three terminal device forming the basis of a Bipolar Junction Transistor, or BJTfor short.
Transistors are three terminal active devices made from different semiconductor materials that can act as either an insulator or a conductor by the application of a small signal voltage. The transistor’s ability to change between these two states enables it to have two basic functions: “switching” (digital electronics) or “amplification” (analogue electronics). Then bipolar transistors have the ability to operate within three different regions:
- Active Region – the transistor operates as an amplifier and Ic = β*Ib
- Saturation – the transistor is “Fully-ON” operating as a switch and Ic = I(saturation)
- Cut-off – the transistor is “Fully-OFF” operating as a switch and Ic = 0
