RC COUPLING :-
is the most Commonly used Coupling Between the two stages of a cascaded or
multistage amplifier because it is cheaper in cost and Very compact circuit
and provides excellent frequency response.
TRANSFORMER COUPLING :-
Impedence Coupling results in more efficient amplification
because no signal power is wasted in Inductor L.
Such Coupling has the drawback of being larger, Heavier and Costlier than the RC COUPLING.
Impedence Coupling is rarely used beyond audio range .
by : Muhammad zubair.... muet student of telecom.
Chat with our AI personalities
rc coupling is a coupling that involves capacitor aand resistor
Its cheaper, smaller in size, and lighter weight than transformer coupling in most cases, while still providing DC isolation between stages. Direct coupling, another alternative, cannot provide DC isolation and therefor tends to make the design of bias circuits more difficult.
The difference between an RC and LC is that the frequency - determining device in the RC oscillator is not a tank circuit. LC can operate with A or C biasing, while RC can only operate with A.
LC means coil capacitance circuit RC means resistance capacitance circuit
The term impedance coupling can be used in two ways. 1) Example, coupling a signal from the output of one stage of an amplifier, to the input of the next stage. For low power as under about 0.1 watt, RC coupling is cheap and adequate as little power is dissipated in the collector resistor of a bipolar amplifier. However at higher power levels impedance coupling is more efficient, but also more expensive. An inductor simply replaces the resistor used for RC coupling. Unlike a resistor the inductors impedance is frequency dependent. This varies the level of coupling voltage available over the amps bandwidth, and needs to be accounted for at the design stage. An advantage is that by the addition of a parallel capacitor, an LC circuit can be formed to produce the basis for a band pass amplifier. Further by providing a tapped inductor; coupling, tuning and impedance matching functions can be obtained. Transformer coupling is a form of impedance coupling and can provide galvanic isolation as well as matching. 2) Unbalanced circuits, that is those having a 'high' or 'signal' lines and a common ground,chassis or earth; have the disadvantage that undesired signal coupling can occur when the higher current signals produce small voltage drops along the common ground. To minimize these undesired voltage variations grounds on PCBs are given wide low resistance tracks. Also by not mixing analog and digital signal grounds, the adverse effects of coupling are reduced. Furthermore, at higher frequencies a narrow length of track also has inductance, and capacitance to nearby conductors. There components provide the possibility of additional undesired impedence coupling. Balanced circuits which do not have one line of any signal grounded overcome the disadvantages of the simpler unbalanced circuits.