Early wireless receivers were beautifully handcrafted, but
were technically primitive. In this time many listeners generally
motivated by the radio broadcasting stations built their own
receivers, using crystals like the galena as a radio wave
detector. Later with the evolution of the valve appeared
in the market the first receivers using only one valve but
unfortunately they were still primitive.
In order to get amplification of the feable radio signals
detected by the antenna, the manufacturers soon started to
launch in the market the first receivers using one or two
valves after the detector. Such new technological approach
by using now several stages arising the well known circuits
topology.
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