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Author Topic: Single Coil Two Transistor Boost Circuits  (Read 56343 times)

Farmhand

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Re: Single Coil Two Transistor Boost Circuits
« Reply #15 on: June 14, 2014, 01:22:18 AM »
OK Gotcha, When the parts arrive I will try the basic RC oscillator (which might be the better option) and the feedback setup a few ways and see what happens.

When the supply voltage gets very low the circuit should go into "burst" mode, where the circuit working draws down the battery voltage till the oscillations stop, then the battery voltage rebuilds and the oscillations happen in bursts that give the same amplitude output voltage of the continuous oscillations (or very close to it) so the bursting oscillator will still charge a capacitor to a higher voltage it'll just take longer.

I have a Galvanic cell with a JT powered by it that lights 2 x 5 mm LED's in bright bursts at about 2 to 12 Hz of 60 kHz oscillations, the supply voltage is less than 0.5 volts RMS by my DMM. It lights the LED's bright but they "blink" so I called it "Blinky Bill"  ;D.

I intend to use that JT to flash at some plants powered by the "pot cell" while at the same time putting current through the soil for electro-horticulture experiments. That setup has been running for weeks now still with the initial wetting of the soil (no more water added yet) still moist, blinking is getting faster it seems. Likely better contact for conduction (less electrode to soil resistance).

Low DC resistance to inductance in a coil is just as important as low resistance switches ect.

..

P.S. Here's a block diagram of what I envision. I already have a less than properly efficient stage 1 - 2 and 3,... 4 can be done by simply adjusting the output of the VLV boost circuit and 5 can be done the same way but an appropriate capacitor dump/current surging charging circuit might be better suited to irregular input/output.

Farmhand

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Re: Single Coil Two Transistor Boost Circuits
« Reply #16 on: June 14, 2014, 03:07:52 AM »
I mainly wanted this thread as a discussion for alternatives to the two winding coil Joule Thief system. So any circuit that can oscillate a single winding coil "like a Joule Thief" or better then it's relevant.  :)

I set up a simple air core Bifilar coil and connected it by one of the windings bottom to the ground and the top of the same winding to a capacitance insulated from the ground, then I connected a variable 40 to 1400 pF capacitor across the other winding to tune it in and then I connected one side of the "tank" to the ground as well and the voltage became much more and the local radio signal looks quite good. See scope shot below. I tuned it roughly to the local 840 kHz - A.M. station.

I would bet that I can use a crystal radio type circuit to rectify that and maybe double it so that a cap can be charged to 0.8 volts or so. 

If not it looks good for a simple crystal setup for one frequency.

Also below is a picture of the coil and arrangement when I took the scope shot, that was BEFORE I connected the tank coil to the receiver coil and doubled the voltage and even before using a top capacitance (going by the photo), so I think one diode voltage drop could still almost double the 1 volt PP. Maybe.

I better set it back up again and check it to the drawing before I post how I connected it, my desktop computer is not fixed yet so I can't use the video camera because no fire wire on the laptop. (I'm lazy like that)

Vortex1

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Re: Single Coil Two Transistor Boost Circuits
« Reply #17 on: June 14, 2014, 03:39:32 PM »
I suggested the diode on the base of the pnp to protect it if you are using a large value C where appreciable current could take out the base junction.

If you are shooting for high frequency operation, the diode capacitance could be a problem, it all depends on what you are trying to design.

As I said, what I posted is the elementary circuit. It was for a variable intensity led flashlight.
I'm used to designing for high volume, lowest cost of components, and best overall performance.

Imagine you had to design a variable flashlight circuit that would sell in the millions of pieces for $1 , and cost of components had to stay under 25 cents.

Where cost is no object there are numerous options.

Farmhand

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Re: Single Coil Two Transistor Boost Circuits
« Reply #18 on: June 15, 2014, 01:15:30 AM »
Hi Vortex, I did mention that you already mentioned about the diode at the PNP base, In a single line statement so you would see it.
I remember. Thanks.

For curiosity sake I ran the circuit down to 0.75 volts last night, but was unable to get it to charge a capacitor to over 3.8 volts at under 0.9 volts input, But three volts no problem.

I'm interested in building prototypes for collecting energy from as many sources for low power devices or for charging their batteries.

One use I just thought of is a light that flashes and can run from the 0.5 volts of a regular pot galvanic cell. I've made one already it is just a joule thief flashing 2 x 5 mm LED's 24/7. I sealed it up in a plastic box to make it waterproof with just the LED ends poking out like eye's, then I glued a light tube over the LED's to keep the light "directed" at the plant. So rather than just shorting out the Pot battery to get current through the soil, I can get light flashing on the plant as well as current through the soil.

Finding the best flashing frequency or frequency of the oscillations in the bursts which light the LED's might require some research.

Anyway, to run from a Pot cell the oscillator needs to have a very small current draw or be able to work in burst mode.

One situation where as much current as I can get is best.

I get current through the soil output and I get light output and I think the plants will benefit from the oscillator near it. Time will tell.

There are a multitude of uses for these type of circuits and extreme efficiency is not always required, especially if the input is free scavenged energy or energy otherwise not usable. Any circuit that works will work. Logically.

..

P.S. As Pirate said and the electro-negativity scale shows that a carbon magnesium battery works best for what we can get a hold of easily. Part of an old Mag wheel for the more negative element and a carbon arc gouging electrode or other form of carbon
for the less negative element. If no Carbon or magnesium then zinc/galvanized steel and copper.

..

Farmhand

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Re: Single Coil Two Transistor Boost Circuits
« Reply #19 on: June 15, 2014, 04:12:00 AM »
The circuit with the PNP and NPN Bipolar transistors shows the below wave form at 0.76 volts input while working into a 25 Farad supercap. With the MPSA18 transistor a better PNP or a single logic gate (which is a bunch of mosfets working as one switch) and Shottky's  , I bet it could go much lower for a small expense in parts.

..

TinselKoala

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Re: Single Coil Two Transistor Boost Circuits
« Reply #20 on: June 15, 2014, 07:51:44 AM »
 8)


magpwr

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Re: Single Coil Two Transistor Boost Circuits
« Reply #21 on: June 15, 2014, 09:50:47 AM »
8)

hi Tinselkoala,

I do admire your work.You do emphasize on "well crafted base" for certain experiments which 18th or 19th century scientist or engineer would do in order to present their invention to the world in a more
appealing approach.Nothing beats the classic way of project presentation.


Dave45

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Re: Single Coil Two Transistor Boost Circuits
« Reply #22 on: June 15, 2014, 01:28:37 PM »
8)
Now thats interesting,
and all this time I thought you were just a follower  ;)

TinselKoala

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Re: Single Coil Two Transistor Boost Circuits
« Reply #23 on: June 15, 2014, 05:13:58 PM »
Now thats interesting,
and all this time I thought you were just a follower  ;)

I see that you aren't familiar with my YT channel.

I neither lead nor follow. I sweep up the candy wrappers and cigarette butts and half-eaten cheese sandwiches that are tossed away by the aficionados following the blind tourguides through the maze of the OC. (overunity catacombs)
While the "fish" are stumbling over the boulders, tripping into streams and bumping their heads on the ever-lowering ceilings on their fantasy tour, I take the bits and pieces they discard, ignore and fail to recognize, and I make beautiful and functional, or at least operational, things with them.
Along the way I try to leave signposts warning of dead ends and blind alleys, but people still ignore the signage and get lost in them anyway. You can hear their pitiful moans and groans and lost scrabbling scrapings, if you listen closely.

Farmhand

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Re: Single Coil Two Transistor Boost Circuits
« Reply #24 on: June 16, 2014, 08:30:50 AM »
Tinsel, Crystal radio ? I guess FM Band ? Nice setup, does it have the jumper for the LED or radio selection ?

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.

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

TinselKoala

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Re: Single Coil Two Transistor Boost Circuits
« Reply #25 on: June 16, 2014, 05:15:37 PM »
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.
Quote

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.
Quote
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

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Re: Single Coil Two Transistor Boost Circuits
« Reply #26 on: June 16, 2014, 10:14:25 PM »
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
..


Farmhand

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Re: Single Coil Two Transistor Boost Circuits
« Reply #27 on: June 16, 2014, 10:47:06 PM »
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.

..

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.

..

Farmhand

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Re: Single Coil Two Transistor Boost Circuits
« Reply #28 on: June 20, 2014, 09:53:07 AM »
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.

..


TinselKoala

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Re: Single Coil Two Transistor Boost Circuits
« Reply #29 on: June 20, 2014, 11:08:47 AM »
I can think of some other things it stands for!

Here is some inspiration:

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