| Block diagrams are a method of explaining complex systems (not necessarily electronic) in a simple manner. They are made up from labeled blocks which are joined by arrows. The arrows indicate the direction of flow, and inputs to and outputs from the blocks. We are told what each block has for an input, and what happens in the block to this input. We are also told what the output from the block is. At this stage it is not necessary to know how the block does its job. That will come later with a greater understanding of electronics. In the example the low level signals from the three microphones are mixed together by the MIXER which gives a mixed low level signal out. The mixed signal is applied to the POWER AMPLIFIER which provides a high level signal to drive the loudspeaker. The POWER SUPPLY UNIT converts the ac mains supply voltage to a dc voltage suitable for the system. Even with this limited knowledge we can apply a little logical fault finding. If there is no output from the loudspeaker but we can measure an output from the mixer then the loudspeaker or the power amplifier is faulty. There would be no point in changing the mixer. With more knowledge one can break the blocks down into smaller blocks and finally the circuitry within the boxes will be understood. There are more pages on this website, being used to explain complex electronics.
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