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A typical example of the use of a common-emitter amplifier is shown in Figure 3. Figure 3: Single-ended npn common-emitter amplifier with emitter degeneration. The AC-coupled circuit acts as a level-shifter amplifier. Here, the base–emitter voltage drop is assumed to be 0.65 volts.
As a result, the common emitter resistor R E acts nearly as a current source. The output voltages at the collector load resistors R C1 and R C3 are shifted and buffered to the inverting and non-inverting outputs by the emitter followers T4 and T5 (shaded blue). The output emitter resistors R E4 and R E5 do not exist in all versions of ECL. In ...
If Q 1 and Q 2 are matched, that is, have substantially the same device properties, and if the mirror output voltage is chosen so the collector-base voltage of Q 2 is also zero, then the V BE-value set by Q 1 results in an emitter current in the matched Q 2 that is the same as the emitter current in Q 1 [citation needed].
In bipolar transistors, as the junction temperature increases the V be drop (voltage drop from base to emitter) decreases. In the two previous circuits, a decrease in V be will cause an increase in voltage across the emitter resistor, which in turn will cause an increase in collector current drawn through the load. The end result is that the ...
Graphs used in network analysis are usually, in addition, both directed graphs, to capture the direction of current flow and voltage, and labelled graphs, to capture the uniqueness of the branches and nodes. For instance, a graph consisting of a square of branches would still be the same topological graph if two branches were interchanged ...
The Wilson current mirror achieves the high output impedance of equation (6) by negative feedback rather than by emitter degeneration as cascoded mirrors or sources with resistor degeneration do. The node impedance of the only internal node of the mirror, the node at the emitter of Q 3 and the collector of Q 2, is quite low. [3]
Since resistors are linear components, it is particularly easy to determine the quiescent operating point of the non-linear device from a graph of its transfer function. The method is as follows: from linear network analysis the output transfer function (that is output voltage against output current) is calculated for the network of resistor(s ...
The current replication ratio may be altered by scaling the transistors, or by the insertion of degeneration resistors in series with the emitters, as was the case with the LH0002. To ensure correct mirroring, T1 and T2 (as well as the opposite pair T3 and T4) must be placed on the die in close proximity or, in case of discrete devices, mounted ...