In this note, we are going to learn about Transformer Coupled Amplifier, about its circuit diagram, working principle, advantages, disadvantages, and applications. Welcome to Poly Notes Hub, a leading destination for engineering notes for diploma and degree engineering students.
Author Name: Arun Paul.
About Transformer Coupled Amplifier
The fundamental reason for the low voltage and power gain of an RC connected amplifier is that the effective load of each stage is reduced due to the low resistance given by each stage’s input to the previous stage. If each stage’s effective load resistance could be improved, the voltage and power gain would increase. This can be accomplished using transformer coupling. Using the transformer’s impedance shifting capabilities, the low resistance of one stage can be reflected as a high load resistance to the previous step.
Transformer Coupled Amplifier Circuit Diagram
Transformer coupling is typically used when the load is small. It is mostly used for power amplification. Figure depicts two stages of a transformer-coupled amplifier. A coupling transformer is used to connect the output of one stage to the input of the following step. The primary of this transformer is used as a collector load, while the secondary is fed into the following step.
Working of Transformer Coupled Amplifier
When an alternating current signal is applied to the base of the first transistor, it is amplified and sent over the coupling transformer’s primary p. The voltage created across the primary is transferred to the input of the following stage via the transformer secondary, as shown in Fig. The second stage provides amplification in a similar manner.
Advantages of Transformer Coupled Amplifier
Here are some merits of this amplifier –
- In this circuit no signal power is lost.
- It offers and excellent impedance matching.
- This circuit offers high gain.
Disadvantages of Transformer Coupled Amplifier
Here are some demerits of this amplifier –
- This circuit has poor frequency response.
- Frequency distortion is higher.
- This circuit is comparatively expensive than others.
Application of Transformer Coupled Amplifier
Here are some uses of this amplifier –
- Used in audio amplifiers.
- Used in communication systems.
- Used in Ethernet interfaces and pulse code modulation systems.
- Used in public address systems and broadcasting.
- Used in oscilloscopes, spectrum analyzers, and other diagnostic tools.