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| Local Oscillator of FM Radio |
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| Scr1bbl3:
Hi all, This is the local oscillator in an FM radio I found. I understand the tank circuit, C10 and C11 function, and biasing. Does anyone know the purpose of C7 and C9? Feedback perhaps but why would you use the 9V power line for the input to output connections? thanks, scribs |
| bsfeechannel:
--- Quote from: Scr1bbl3 on February 22, 2021, 03:36:55 am ---https://app.photobucket.com/u/scr1bbl3/p/d884f174-e534-4e5b-99d0-aada2ee9cdb7 --- End quote --- Do I have to log in? |
| Alex Eisenhut:
The owner of this album has set this album to private. |
| Zero999:
--- Quote from: Scr1bbl3 on February 22, 2021, 03:36:55 am ---Hi all, This is the local oscillator in an FM radio I found. I understand the tank circuit, C10 and C11 function, and biasing. Does anyone know the purpose of C7 and C9? Feedback perhaps but why would you use the 9V power line for the input to output connections? thanks, scribs https://app.photobucket.com/u/scr1bbl3/p/d884f174-e534-4e5b-99d0-aada2ee9cdb7 --- End quote --- Please attach the schematic to a post, rather than using an external image hosting site. In the past we've had problems with hosting sites deleting images, so the thread no longer makes sense. When you're editing the post, click Attachments and other options to attach the image to the post. |
| bsfeechannel:
--- Quote from: Scr1bbl3 on February 22, 2021, 03:36:55 am --- --- End quote --- Now we're talking. This is a Colpitts oscillator. C9 is part of its feedback loop and C7 is decoupling the base of the transistor. |
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