Uhhh...This is a working AM radio design, assuming it has been transcribed correctly. Any ideas for improving the sound output level?View attachment 320967
But semiconductor diodes!!! I'd think you'd boot up some proper tube diode detectorsHere's a better one.
No pesky tubes nor transistors.
Good antenna required.
View attachment 320978
source: http://www.fmamradios.com/XtalTuner.html
The detector can be a modern semiconductor diode, a galena crystal, or delightfully low tech.
Foxhole radio - Wikipedia
en.wikipedia.org
One may build an FM radio in broadly similar fashion.
View attachment 320979
source: http://electronbunker.ca/eb/FMCrystalSet.html
That wouldn't be nearly so green!But semiconductor diodes!!! I'd think you'd boot up some proper tube diode detectors
A small steel wire poking a galena crystal. Go old school.That wouldn't be nearly so green!
Repurposing an old razor blade and a pencil to a detector -- now that's upcycling.
If hipsters made AM radios...
Do you -- and this isn't meant to be a snarky question! -- understand how a superheterodyne AM radio circuit works? The long wave (radio frequency, RF) radio signal is picked up by an antenna, amplified (or not), mixed with a local oscillator to produce an intermediate frequency (IF) signal which is amplified, filtered, then detected and used to drive an audio output stage. Look at a simple, classic AM radio design such as an "AA5" five tube vacuum tube radio as your model and guide.Jeez, did not expect this many responses so quickly. This is a project for an engineering class I’m in. I have only a basic understanding of how this works, and this op-amp implementation seems quite different from others I have seen. We only have access to these materials at the time, with some other capacitors if we need. Does anyone here know how I might improve this design or create a better one with these materials? Idk
Turn that in for your grade and I guarantee your prof will be impressed!Do you -- and this isn't meant to be a snarky question! -- understand how a superheterodyne AM radio circuit works? The long wave (radio frequency, RF) radio signal is picked up by an antenna, amplified (or not), mixed with a local oscillator to produce an intermediate frequency (IF) signal which is amplified, filtered, then detected and used to drive an audio output stage. Look at a simple, classic AM radio design such as an "AA5" five tube vacuum tube radio as your model and guide.
View attachment 320984
(note that the 12AV6 tube has three functions built into it -- two diodes and a triode)
source: https://www.worldradiohistory.com/B...ooks/RCA-Receiving-Tube-Manual-1960-RC-20.pdf
We may have already discouraged a budding RF engineer. C'est la vie...I guess it wouldn't be good to mention superregenerative radio circuits now, would it?
All that. And last I checked, a 741 has almost no gain in the AM broadcast band. So even if the circuit "worked" it would be crap. Use solderdude's circuit. Well, unless that 5-tube superhet is calling your nameThis circuit cannot possibly work correctly for the simple reason the + input of the opamp is floating (not connected) so the opamp output will go either to + output rail or - output rail voltage.
You either need a detector in there and use the uA741 with tons of gain (and properly used !) or you need to get yourself a ZN414, 415 or 416.