Easy 2 transistor Wien Bridge Sine wave oscillator 5 Hz - 33 KC schematic & demo and more, read text
Please read the description/textbox first & the corrections. There are (sorry) a few major corrections to tell about this video though it is OK when you have a basic understanding of electronics, in that case you will see immediately what is happening or goes wrong here.
NEXT VIDEO (9 Nov 2022), with simple amplifier that can beef up the 0,3 Volt AC output to max. 20 Volt AC is here • Easy 2 transistor Wien Bridge Oscilla...
Video + schem. of an easy to make 2 transistor sine wave generator. Now with 0,2 V-0,3 V AC out.
Of course everything in this very simple setup must be tuned “by hand” (!) (demo in the video).
That does not have to be a problem for everyone interested in serious electronic/oscillator experiments.
So it gives features that the Ali website sine wave generators (of 7-10 Euro’s/Dollars, often made with the XR 2206) don’t have.
Say protection to ground faults, protection to a too high voltage on the input, etc.
VERY IMPORTANT issue is this: I published this circuit on the LULU website many years ago. I made it/re-tested it now on 4 Nov. 2022 and I found that the solution of the “bicycle lamp of 6 V at 0.3 Watt” did not want to work always! That is a shame for me….
I tested 10 bicycle lamps during the past days (all “6 Volt at 0.3 Watt”), they were incandescent lamps made by different manufacturers. Their DC filament resistance varied between 30 Ohm and 60 Ohm.
None of the bicycle lamps (6 V at 0.3 Watt) wanted to work…. Except 1 (!) of them.
It /that specific lamp had a DC resistance in the 50 Ohm range.
Example: thus I tested (after this conclusion) a few Christmas tree incandescent lamps, switching them into a 50 Ohm figuration, some of them worked too.
Finally I decided: use a 100 Ohm wire wound potentiometer to set this basic Sine Wave oscillator unit to its working point/bias. That was the best solution. Why wire wound? Because the alignment can be so precise as needed.
CORRECTIONS & MORE to this video:
1. On 7.57 I talk about a link to a simple audio amplifier, that can do this job, of lifting up the say 2 V AC out of the Sine Wave generator, to approx. 8 V AC. I have made it, it worked, I will show the precise schematic in the future. Anyway: that simple audio amp that I am going to use here is already on my YT Channel. Link: • Mini audio amplifier on 0.3 Watt 6-12...
2. That simple audio amp also (after a test) proved to work on 24 Volt, so I could use it to get (say) 8-10 Volt AC out when connected the sine wave generator (that had original 2 V AC out). The end-coupling capacitor out of this simple (BC 547-BC 557) amp. at 24 V DC is now 2 uF at 400 Volts, input cap. Is 0,47 uF at 400 Volts.
3. The earth/ground connection of the sine wave generator can be switched “off”. In that case it is decoupled for DC with a 400 Volt at 0.47 uF capacitor. So that AC can pass and ground faults/loops can be eliminated.
4. On 11.51-11.54 I talk about capacitors in the uF (Micro Farad….) range, in the oscillator unit, that is of course nonsense (!). Very sorry for that mistake! & see/study the schematic. Caps are 1 uF non polar, 100 N non polar (=0.1 uF) and 10 N (0.01 uF) non polar.
5. On 12.24 of the video: I tried to “overlap” the lower frequencies by switching on (in fact overlapping) the capacitors in the bridge (1uF-100N-10N) with a capacitor of 120 N. That only can/will have an effect on the lowest frequencies of this sine wave generator, making it possible to overlap the lowest frequency bands, say going from 20 Hertz to 200 Hertz.
6. OF COURSE on 12.33 I am not (!) talking about electrolytic capacitors, very sorry for that (!). I am only talking about non polar capacitors in the 470 N (=0.47 uF) range that can work from 400 Volt to (say) 500 Volt.
My You Tube channel trailer is here: • Radiofun232 on YouTube. Updated month... When you search, search always “NEWEST FIRST” to get the right overview.
You can also search via the “looking glass” on my Channel trailer via keywords like ”audio”, “radio”, “amplifier”, “filter”, “Shortwave”, “transistor”, “FET”, “oscillator”, “generator”, “switch”, “schmitt trigger” etc; so the electronic subject you are interested in.
My books about electronics & analog radio technology are available via the website of "LULU”, search for author “Ko Tilman” there.
https://www.lulu.com/search?adult_aud...
I keep all my YT videos constant actual, so the original video’s with the most recent information are always on YouTube. Search there, and avoid my circuits that are republished, re-arranged, re-edited on other websites, giving not probable re-wiring, etc. Some persons try to find gold via my circuits. I take distance from all these fake claims. I cannot help that these things happen. Upload 6 November 2022.
My YT Channel Radiofun232 can disappear suddenly. Reason: I am shadow banned and censored by You Tube/Google because I have posted critical comments about the Covid vaccinations, say about side effects etc.
