Society of Robots - Robot Forum
Electronics => Electronics => Topic started by: airman00 on May 11, 2008, 10:56:04 AM
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Anybody know if a variable resonator exists? and where I can buy it from?
EDIT: not like a radio which takes power to receive . I want to harness the piezoelectric effect from a variable source - basically get electricity from a variable resonance crystal , or maybe a different medium
thanks,
eric
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check out TXCO - temperature controlled crystal oscillator.
variating the core temparuture variates the main frequency
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hmmm
im looking for something that is variable crystal without putting in energy , like mechanical turning or something
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you could put a variable capacitor in series with a the cristal it dos change the frequency to some extent but the best way to go is just use a 555 or if you need higher frequencies like 100KHz and up you could use a tank circuit witch is just a capacitor and an inductor in parallel you can change the frequency by changing the values of the inductor or capacitor.
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I'm looking for a receiver for signals <30 hz
does that exist? thats why I want to be able to variably tune it
would the crystal and variable capacitor work?
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30 Hz is too low. Why not just take MCU and generate required frequency with high resolution and accuracy?
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generally you should use at least 100kHz or more for RF. what are you using it for? I have many receiver schematics laying around if you like I can post one.