The BJT must be biased properly to get a correct output. The carrier is connected to the base and this is amplified by the BJT and flows in the collector, but again the current is restricted by the opposing flow from the modulating wave connected to the emitter. As a result the output amplitude is varied according to the opposing modulating voltage. One thing should be maintained in the AM circuit. That is that the message signal voltage (Vm) should be less than the carrier voltage (Vc). This relationship is known as the modulation index (Vm/Vc) and it should be between 0 and 1. When it is more than 1, or if the Vm is more than Vc, then distortion occurs. Let’s see the output of the above circuit – the modulated wave.