Transformer coupling introduces what type of distortion

Now the voltage developed across P is transferred to the input of the next stage by the transformer secondary S. The second stage now performs the amplification in an exactly same manner. The frequency response of a transformer coupled amplifier is shown in the figure below.

It is clear from the above fig. Since, the output voltage is equal to the collector current multiplied by reactance of primary, hence at low frequencies, as the reactance of primary begins to fall , the output voltage also decrease and hence the gain.

At high frequencies, the capacitance between turns of windings acts as a bypass condenser to reduce the output voltage and hence the gain. Due to these two factors, there will be disproportionate amplification of frequencies in a complete signal such as music, speech etc. Hence, transformer coupled amplifier introduces frequency distortion. Normally the last stage of a multi stage amplifier is the power stage. Here it is required to transfer maximum power to the output device for example a loud speaker.

The gain of the amplifier is constant only for a small range of frequencies. The output voltage is equal to the collector current multiplied by the reactance of primary. At low frequencies, the reactance of primary begins to fall, resulting in decreased gain. At high frequencies, the capacitance between turns of windings acts as a bypass condenser to reduce the output voltage and hence gain.

So, the amplification of audio signals will not be proportionate and some distortion will also get introduced, which is called as Frequency distortion. Transformer Coupled Amplifier Advertisements. Previous Page. Next Page. Previous Page Print Page. Save Close. Dashboard Logout. Usually, the impedance of an output device is a few ohms whereas the output impedance of transistor is several hundred times this value. In order to match the impedance, a step-down transformer of proper turn ratio is used.

The impedance of secondary of the transformer is made equal to the load impedance and primary impedance equal to the output impedance of transistor. The output device e. Previous Next. Questions of this topic.

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