in certain power amplifiers(cls A,cls C etc.) the output sometimes not directly taken. rather it's coupled with transformer and then transferred power is applied to the load..this is transformer coupling.....
there are two main reasons to do so
1. in order to increase the efficiency.(exmpl: efficiency of class A power amplifier increase by almost 25%)
2.in order to get smooth i.e; distortion less output..
by Jishnu Mukherjee
(Kolkata,India)
transformer coupling ensures maximum power transfer is obtained even if the output impedance is not equal to the load impedance
transformer coupling
no.transformer coupling gives higher gain
Transformer coupling
1)rc coupling 2)transformer coupling 3)direct coupling
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.
An ordinary transformer uses mutual inductance to transfer energy from one circuit to another, while resonant coupling energy transfer utilizes resonance between the coils to enable more efficient energy transfer. Resonant coupling allows for wireless power transfer over larger distances compared to traditional transformers.
A transformer relies on electromagnetic coupling to transfer power between two electrically isolated circuits. The transformer may step-up or step-doen the voltage or even perform 1:1 transformation for isolation purposes.
an RC coupled amplifier is basically used for voltage amplification , where the circuit currents are quite low. higher currents & voltages would mean more dissipation in the load resistors , which is essentially very lossy . The coupling amplitude to the next stage is ideally the same as the previous stage signal excursion. However if a transformer is used for coupling , both large voltages & current can be handled without incurring the dissipation of a resistive load. Moreover a coupling gain of the transformer primary to secondary ratio is also a bonus. also because of the possiblity of correct impedance matching on the primary & secondary side maximum power coupling is obtained. hence transformer coupling is more efficient in such applications. in high frequency applications transformer coupling , along with tuned circuits as applicable is the choice circuit.
A transformer relies on electromagnetic coupling to transfer power between two electrically isolated circuits. The transformer may step-up or step-doen the voltage or even perform 1:1 transformation for isolation purposes.
NO. Transformer coupling gives the higher gain in case of amplifer.
Link coupling is used to transfer energy between two r-f circuits which for whatever reason cannot be located near to each other. The method used in link coupling is a wire loop which stretches between the two stages, terminating at each end in a coil of few turns. At the output of the first stage, this wire loop will act as a step-down transformer, and at the input of the next stage it will act as a step-up transformer. To work in this manner the loop terminations must be positioned next to the inductor of the r-f tank circuit.