Wien Bridge osc.

George Herold · 2012-02-16T01:11:23+00:00

The latest project* has a gang of Wien bridge oscillators.The gain section is two back to back diodes and R's +-||--+ +--+0.51 R+--1.5 R-+ | | | | +-----------|- | | | >---+ R RC stuff-|+/ | |/ GNDThe diodes are just clipping off the top. So there's less distortion.I got a bit better than 60dB (3rd) with the above. (with R=1k Ohm)You can play with the 0.5/ 1.5 ratio and get higher voltage andperhaps less distortion.The even harmonics depend on matching the diodes.Any suggestions?(I think I used diode connected transistors.) But matched diodes areOK too."Matched" transistors or diodes seem to cost the earth.(I can train someone to match them for less.)Lot's of dual'sGeorge H.*The thumbprints of the SED are *All Over* (or under) the beautifulfig. 2 on pg. 1.Thanks guys, I feel in great beer debt.

Feb 16, 2012 41 Replies

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George Herold 14 years ago

est project* has a gang of Wien bridge oscillators.

Thanks LM, I've seen the thermistor trick, but I've never tried it.

George H.

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Ben / SM0KBW 14 years ago

Another old trick is to use a small lamp in the feedback net. Lamps has PTC characteristics. Take a look at

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or just use google to see how it's done.

/Ben - SM0KBW

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