WAEC SSCE Electronics
Study notes for AMPLIFIERS — part of the WAEC SSCE Electronics syllabus. 1 learning objectives with explanations and exam tips.
A voltage amplifier is an electronic circuit that takes a weak electrical signal and makes it stronger without changing its shape or pattern. Think of it like a megaphone at a football match in Lagos—the sound goes in small, but comes out much louder and clearer to reach the entire stadium.
The main job of a voltage amplifier is to increase the voltage of an input signal many times over. This multiplication factor is called the voltage gain. For example, if a small signal of 0.1 volts enters a voltage amplifier with a gain of 100, the output becomes 10 volts—much stronger and ready to do useful work.
Voltage amplifiers are everywhere in Nigeria. Your mobile phone's microphone uses one to amplify voice signals before sending them through the network. Without amplification, nobody would hear you on a call.
The amplifier must have a power supply to boost the signal, and the output signal should remain faithful to the input—just louder, not distorted.