Single Coil Two Transistor Boost Circuits

[TinselKoala]

Tinsel, Crystal radio ? I guess FM Band ? Nice setup, does it have the jumper for the LED or radio selection ?

Yes, crystal receiver. No, not FM, just ordinary AM standard broadcast band. I do have a couple of designs for FM broadcast crystal sets but they are something else entirely, requiring careful construction because of the high frequencies.
The LED is just permanently in circuit, in parallel with the output. Many crystal radio circuits put a resistor and capacitor filter across the output. I didn't see any effect of that on this unit so I left it off, and the LED will often light up even when the audio output is also in use.

If I had a better function generator I would go for a mHz radio because there is more power there I think, some of the mHz stations just south of here are a lot higher power than the one AM station just north of here, when i say just north it's 30 klm and south is about the same or a bit more.

More power in the transmission perhaps, but harder to deal with using "garage technology" because of the high frequencies. Also more subject to line-of-sight transmission paths. You don't get much "skip" at FM broadcast frequencies, but sometimes you can pick up strong AM standard broadcast stations for thousands of miles.

Can you explain the arrangement for me please, it is relevant due to being an emergency source of light and radio messages of a safety nature.

All low voltage sources of power around that we can use will apply to these circuits, thanks for posting. Safety is always relevant.

Cheers

Sure, I didn't mean to hijack your thread, but as you say it's relevant, and illustrates several important principles, like sympathetic resonance and the use of natural materials, and of course the "variometer coil" tuning trick. This is kind of a single-coil that allows one to flip over half of it without disconnecting. I think a properly built one could smoothly transition between fully "bifilar" behaviour (very small inductance) to full monfilar multilayer air-core behaviour with relatively large inductance. This one goes from about 100 uH to about 160 uH ( or at least it did before I took a few turns off for tuning to 1200 kHz. A little lower figures now.)

I plan on building a tunable coil like this for JT use. It will need some more wire than this one, though, since it's air core, to reach the needed inductances for JT behaviour, I think.

I got the basic idea for the setup from the Heart of England crystal radio club, which in turn posted an article from Popular Wireless magazine from 1925 detailing the coil construction. Look at these beautiful builds of ancient designs:
http://crystalradioclub.co.uk/g4wpw.htm

Here's a video I just uploaded, demonstrating the "Australia" Variometer Galena Crystal Radio.
http://www.youtube.com/watch?v=cBEhtzGcYW4

I hope I don't get flagged for "copyright violation" since there is some AM broadcast music heard. YT actually flagged me for some motor noise in an earlier video, even "identifying" the specific source, some weird CD of electronic music. But I had no music, just motor noise! So I disputed it and a few days later the flag was removed. Some human at YT probably got a bit of chuckle out of that.

[Farmhand]

Yeah you tube tried that on me too but I disputed it as well and had the flag lifted, they do it so they can force advertisements on people. They threatened me with legal action and yet there was no copyright infringement, they should be prosecuted for harassment. Basically if your neighbor plays loud music and you make a video they foist copyright infringement action on you, but it's ok by them as long as you allow them to place free ads on the video. If the copyright was actually the point to it they would just demand it be removed period. I would argue in court it has nothing to do with copyright and only to do with forcing ads on people, even on those who capture content that cannot be heard by the human ear, as well as anything the "machine" thinks might sound like copyrighted content. Once you make a successful dispute they should leave you be as they know they are wrong legally. It's all bluff.

Having said all that if we do place a video with a radio station playing, as long as we mention the music is courtesy of the radio station "Mention Name" and they are the ones playing the music, then we should be fine as we are not claiming anything is "our" content.

I think once they get a dispute over a copyright infringement where they are clearly wrong that they remove your channel from the scans. For fear they will be prosecuted for false copyright infringement claims or harassment, if they make several false copyright infringement claims on the same person then they can be prosecuted for harassment because that is what it is.

I urge all to dispute any BS copyright claims made by you tube "on the behalf of artists", because that is not why they do it.

Anyway, I see you use an antenna, I just use a Tesla coil as the antenna and a ground connection (isn't that what a Tesla coil is anyway a "Transceiver", I can listen to the radio with a Tesla coil tuned to 833 kHz, no need for an outside antenna. I think there is a practical advantage to that in that I can get radio to listen to without  even going outside. I can use piezoelectric ear buds or by using a very small amplifier that runs from a AAA battery.

I can also "locally" block a band out of the middle of the tuning range for the 833 broadcast on a hand held regular radio by tuning in the Tesla coil under power in continuous wave mode. It makes a real neat totally silent space in the middle of the tuning range, hilarious. 

Cheers


P.S I was using the Tesla coil one day with solid state switching, " just out of tune and making plasma streams" and the "noise" could be heard several kilometers away on a car radio, the person was on the way to my home and as he got closer the noise got more then he said as he drove up the driveway it stopped, that's because I turned it off when I seen him coming so I could go talk to him. hahahahha
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[Farmhand]

I got some of the ordered parts from one place and so I was able to put some 1N5819 diodes in the prototype, I also changed the variable 800 uH - 3.3 mH coil from the secondary circuit to the VLV two transistor circuit which lowered the frequency to a range between 3 and 13 kHz and now the wave form looks much better on that circuit. On the secondary circuit I changed to a 37 uH coil and using 2.5 uS I can get the power output I want at only 45 to 60 kHz even though the circuit can work up to 800 kHz as it is.

Out of curiosity I set up another three gate oscillator on the other vacant side of the CD4049 and I got it to oscillate at 1 mHz no problem and fairly stable with only 3.5 volts input, I think on a board it would work even better, It needs at least 50 pF timing cap to be stable. If I just put a 100K resistor across one gate it oscillates at 4 mHz but the signal is curvy.  A "odd number gate" ring oscillator is easy as well.

The CMOS cookbook says this CD4049 chip can make a good several mHz oscillator, it also shows a circuit for a square wave generator from a few Hz up to HF. Very handy book.

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P.S I think if I want to use a logic chip as a second stage oscillator (3 to 5 volt) and use some of the gates for "control" turning off and on other parts of the set up, then I should use a Schmitt trigger chip or regular CMOS chip (not a CD4049), then I can use a rising and falling divided voltage to trigger a gate to change it's output. Maybe. Logic chip = 25 cents but a picaxe 08M2 = 3 or 4 dollars.

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[Farmhand]

Wow does SMD stand for "Super Minute Devices" or "surface mount devices", these things look like fleas stuck to a piece of tape.
I'll need to sharpen my soldering iron point, find some tweezers and solder some pins on one of each part to prototype with. Or maybe I can make some tiny adapters with little bits of circuit board. I've got PCB making gear to make a simple tiny board.
My oh my so tiny.  Will make a compact circuit though.

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[TinselKoala]

I can think of some other things it stands for!

Here is some inspiration:

http://www.youtube.com/watch?v=-KMLmpC7-Ls