Class A Amplifier: Pros And Cons
An audio amplifier is generally referred to as a device which is able to multiply an applied input signal amplitude to a level that may be much higher than the applied one. The input is mostly in the form of an audio or a music signal. These amplifiers are basically classified into class A, class B, class AB, class C and class D. Here we will discuss regarding the technical specifications of the first type of amplifier i.e. class A amplifier and also learn how to build a simple DIY class A amplifier.
Amplifiers are generally specified as highly efficient due to the fact that these amplifiers conduct only during the presence of an input signal and thus only the input signals are actually boosted.
Contrary to this, class A amplifiers are quite badly reputed as far as their efficiency is concerned. Class A type of amplifiers may conduct at full swing, round the clock as long as the supply power is ON, irrespective of the applied input signal, making the output transistors sizzling hot, unnecessarily dissipating a lot of power in the form of heat. This happens because the transistors here operate through the entire 360 degrees of the input periods i.e. during both the negative and the positive half cycles. Thus its quiescent current drain is very high almost equal to the maximum power it is normally supposed to deliver.
When it comes to designing an amplifier, class A topology may be considered as the most fundamental.
But all the above mentioned drawbacks of the amplifier are to some extent compensated by a few of its remarkable qualities which are as follows:
As far as the sound output quality goes, class A amplifiers are considered to be one of the best.
With almost no cross over distortions and a linear response, the sound output from these amplifiers are distinct and most pleasing to hear.
A simple circuit design of a class A amplifier presented here can be easily built and its above behavioral patterns may be studied, let's see how we can do it.