Simple Inverter

[SkyWatcher]

Hi folks, gadgetmall found this circuit and posted in other forum.
Was looking for something to do, while the SSG charges batteries, so whipped up this circuit with a transformer had already rewound with bifilar 24awg. primary and 30awg. secondary, works well for 12 volt input.
Used salvaged 2 amp 1watt small PNP transistors, though larger 2n3055's NPN can be used also and 10kohm resistors were used.
It can power this 3 watt RGB led color changing bulb no problem and when lowering resistor values to 4.7kohm, can power a 5 cd changer/radio boombox that says 25 watts input, though this inverter only draws around 9 watts with it and the transistors barely get warm, which seems odd.
Just thought would share, since it has such low part count and works real well. Normally these use capacitors also in oscillator stage, this doesn't, it uses the coils capacitance instead to perform the same function.
The bifilar coil is used in my setup and for the center tap connection, the end of the first primary strand is connected to the beginning of the second primary strand.
Here is circuit, site calls it a micro inverter and pics of me setup.


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peace love light
tyson

[SkyWatcher]

Hi folks, just to show the usefulness of this simple circuit, here is a video powering a boom box with cd changer and a 3 watt color changing led bulb, draws 5 watts at 12 volt input when white color is used and 3 watts with all other colors.
Also tried a smaller ferrite e-core that has 24 awg. bifilar primary and 30awg. secondary and it also powers the 3 watt led bulb nicely, though the resistor values had to be changed to 500 ohms, using 3.8 volt lap top battery.
It does run down to 1.2 volt input also, which is useful, as the typical flip flop oscillator usually requires 12 volts.
So this could easily power the led bulbs folks are using, with minimal parts and small transistors as they don't seem to heat up much at all.
Here is a pic of the ferrite e-core running the led bulb on white color setting and a video of the standard 12 volt transformer setup.

Simple Inverter Astable Oscillator - YouTube



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Any comments are welcome and if you build this simple circuit, let me know how it works out or if you have any questions, thanks.
peace love light
tyson

[totoalas]

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Thanks Skywatcher
Ysing 8 v dc sla battery with 3 watts load

I can also charge cell fones with no heat at all

totoalas

[Zardox]

What is the purpose of the capacitor across the high voltage output? Does it have effect on the frequency or is it needed for the circuit to oscilate? I am wondering if it might be useful in some other circuits like the joul ringer.

[SkyWatcher]

Hi totoalas, thanks for the reply, glad you found the circuit useful and it works well for you.
Hi zardox, thanks for reply, the capacitor on secondary output will affect frequency, depending on value and also probably helps make a more sinusoidal ac wave.
Hope that helps.
I'm boxing this circuit up with the small ferrite e-core and 3.8 volt lap top battery to solely power a 120vac led bulb.
peace love light
tyson

[Bodkins]

cool stuff man

[SkyWatcher]

Hi folks, Hi bodkins, thanks for reply and kind words.
Boxed up the smaller portable version of the simple inverter.
Using CD case, ceramic lamp base hot glued to top and prettied up.
Smaller ferrite e-core using 3.9 volt lap top battery.
It can power smaller things like led strings and lower power led bulbs meant for 120 volt AC, though can be wired for 220 volt AC.
Going to box up a little higher power version using 12 volts and bigger laminated steel transformer as shown earlier, so it can power radios, cfl's, chargers, etc.
Here is a pic of the simple inverter peace power supply and a video of it.
Simple Inverter Astable Oscillator boxed using CD case - YouTube



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peace love light
tyson

[Matthew Jones]

Have you looked at the wave form? I would guess it was more modified sine then pure sine but I was just wondering.
Also what hertz is it running?

The cap (C1) is in place to hold down spikes.

I suppose if you knew the hertz and the max current per leg you could build a small IC filter to curve out the waveform. But you would only want that if you were right at 60 hz (50hz Europe). Other wise you might as well keep it square.

Adjusting the hertz would most likely not be that big of a challenge.

Nice and simple though.

Matt

[Matthew Jones]

Multivibrator

This a paper on an improved Astable Multivibrator That will help you adjust your timing. The only difference in it you are using and induction on the discharge path as opposed to resistance. You should see what I mean.
If you wanted to calculate the Hertz and adjust to it you math will change slightly. But basically hit it pretty close by measuring the resistance of you windings and putting that into the calculation.

Hope that helps some.

Matt

[SkyWatcher]

Hi folks, Hi matt, thanks for the helpful information.
Was looking for something simpler to drive these salvaged mosfets and it works fairly well as a radiant charger.
Though you don't have to use both sides, if you use only one side for the gate trigger signal, you can put all the windings on one coil form or core.
Though if you use both sides, the coils have to be separate.
Your thoughts appreciated.


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peace love light
tyson

[Dave45]

Asymmetrical circuits for asymmetrical coils
Awesome keep up the good work.

[Dave45]

[SkyWatcher]

Hi folks, Hi dave, thanks for reply and kind words, that is an interesting coil arrangement you show, how would that coil setup work, thanks.
Decided to try and run the joule ringer 3.0 ferrite bead core with one side of this mosfet astable circuit.
It is 8" long glued together ferrite beads with one layer of 30awg. and one layer of 75 turns of 20 or 22 gauge speaker wire.
With 12 volt battery input, it lights up a 13 watt ungutted cfl nicely and small heatsink gets slightly warm on mosfet.
Though the 3 watt led bulb tried just flickers all over, think because it has a microprocessor for the color changing bulb, that is why, other normal led bulbs would probably work fine.
It also lights a 15 watt cfl and a 40 watt incandescent to half brightness.
The 2n3055's used in the astable oscillator section do not need to be that large, small NPN signal transistors or medium size should work fine also.
The 30 awg. secondary is directly attached to output load, not wired like joule ringer at all.
Just though to see if this would work and it did, nicely.
Here is pics.


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peace love light
tyson

[Dave45]

Good work, asymmetric coils have been used before, one side produces voltage and the other amperage.
Here's an experiment done by Woopy, you may have seen it Amazing melting with low power transformer 1.wmv - YouTube

I think it can be done using a solenoid configuration like the JR 3.0 but using two one wound cw and the other wound ccw and placed end to end, they should work together.

Notice in the Woopy configuration he runs one secondary into the beginning of the other, current trailing voltage.
hope I gave you some idea's
Stay asymmetrical

dave

[Nick_Z]

Skywatcher:
That's nice that you made the core the full 8 inches, with similar winds as the 3.0 version rod. It may not work quite as well as the $30 rods that LS uses, but the beads don't cost much, if anything either, and they do work, with only slight ringing when using the higher current bulbs.
The TIP 3055 works almost as well, too, but each transistor is a little different, and some heat up more than others also, especially the small ones.
Maybe others will see how easy and well this system works, even with those ferrite beads, or the CRT yokes, also.
If I can obtain a few more beads I'll make my core longer, also.
But, I found that more turns in not always better, especially on the secondary, as it's important to have the proper turns ration. Too high a voltage is not good, at the expense of the current level.
Great work....Sky