13-09-2013, 02:09 PM
CE, CB, CC Configurations:
Configurations.doc (Size: 735.5 KB / Downloads: 383)
Transistor Configuration:
We know that transistor has three terminals namely emitter(E), base(B), collector©.
However, when a transistor is connected in a circuit, we require four terminals (ie) two terminals for input and two terminals for output.
This difficulty is overcome by using one of the terminals as common terminal.
Depending upon the terminals which are used as a common terminal to the input and output terminals, the transistors can be connected in the following three different configuration.
1. Common base configuration
2. Common emitter configuration
3. Common collector configuration
Output characteristics:
Diagram
The emitter current IE is held constant at each of several fixed levels. For each fixed value of IE , the output voltage VCB is adjusted in convenient steps and the corresponding levels of collector current IC are recorded
.For each fixed value of IE, IC is almost equal to IE and appears to remain constant when VCB is increased.
Diagram
The operation is much similar to that of C-E configuration.When the base current is ICO, the emitter current will be zero and consequently no current will flow in the load.
When the base current is increased, the transistor passes through active region and eventually reaches saturation. Under the saturation conditions all the supply voltage, except for a very small drop across the transistor will appear across the load resistor.