Search results
Results from the WOW.Com Content Network
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.
Capacitive coupling is the transfer of energy within an electrical network or between distant networks by means of displacement current between circuit(s) nodes, induced by the electric field. This coupling can have an intentional or accidental effect. Capacitive coupling from high-voltage power lines can light a lamp continuously at low intensity.
Conversely, a voltage follower inserted between a small load resistance and a driving stage presents a large load to the driving stage—an advantage in coupling a voltage signal to a small load. This configuration is commonly used in the output stages of class-B and class-AB amplifiers. The base circuit is modified to operate the transistor in ...
Nevertheless, this use is still relevant in the 21st century because tubes and tube amplifiers continue to be produced for niche markets. In analog telecommunications systems center-tapped transformers can be used to provide a DC path around an AC coupled amplifier for signalling purposes.
That is, an active load imposes less restriction on the output voltage swing. Notice that active load or not, large AC gain still is coupled to large AC output resistance, which leads to poor voltage division at the output except for large loads R L ≫ R out. For use as a current buffer, gain is not affected by R C, but output resistance is.
In electronics, electric power and telecommunication, coupling is the transfer of electrical energy from one circuit to another, or between parts of a circuit. Coupling can be deliberate as part of the function of the circuit, or it may be undesirable, for instance due to coupling to stray fields .
A fully differential amplifier (FDA) is a DC-coupled high-gain electronic voltage amplifier with differential inputs and differential outputs. In its ordinary usage, the output of the FDA is controlled by two feedback paths which, because of the amplifier's high gain, almost completely determine the output voltage for any given input.
Transformer coupling is an alternative AC coupling. Like RC coupling, it isolates DC between stages. However, transformers are bulkier and much more expensive than capacitors so is used less often. Transformer coupling comes into its own in tuned amplifiers. The inductance of the transformer windings serves as the inductor of an LC tuned circuit.