- #1
Cool4Kat
- 45
- 13
Hi, I am researching the early history of electricity and I would love some help.
So, in the very early 1900s (like 1906) there were several items created that were diodes (crystals, Fleming valve, electrolytic detector). As far as I understand, people would use these diodes to convert the AC from the signal into pulsed DC with a diode and thus were able to hear the radio buzzing with their headsets. Now humans can hear up to around 20 kHz, which implies that the maximum frequency that this method would work for is 40 kHz.
In 1918, Armstrong invented the superheterodyne to work for super high frequencies (above 500 kHz). So, here is my question. How did they "hear" any frequency between 40 kHz and 500 kHz before then?
What am I missing? Very confused.
Thanks
So, in the very early 1900s (like 1906) there were several items created that were diodes (crystals, Fleming valve, electrolytic detector). As far as I understand, people would use these diodes to convert the AC from the signal into pulsed DC with a diode and thus were able to hear the radio buzzing with their headsets. Now humans can hear up to around 20 kHz, which implies that the maximum frequency that this method would work for is 40 kHz.
In 1918, Armstrong invented the superheterodyne to work for super high frequencies (above 500 kHz). So, here is my question. How did they "hear" any frequency between 40 kHz and 500 kHz before then?
What am I missing? Very confused.
Thanks