Single Coil Two Transistor Boost Circuits

[Farmhand]

I think the transistor is funky, it won't work with 1.25 volts but does work with 1.16 volts, weird. Anyway, when the mosfets arrive I'll do more proper testing, this big PCB is more or less a PCB prototype, I can change stuff pretty easy but much better performance and less jitter than the solderless board. I'm going to increase the frequency, reduce the on time and try a MPSA18 transistor for something to do. I'll try 18 K and 10 K for the timing resistors and the timing capacitance can be 200 pF. Should get it up over 100 kHz and keep oscillator power down, by keeping a small timing capacitance. And hopefully if a higher frequency low voltage mode occurs it will be even higher than 325 kHz but cause a bit less power draw at low voltage. It actually lit the LED's better in the high frequency low voltage mode than in the regular mode. I've got a capacitor across the diode and circuit ground so I've got more or less DC with bumps across the LED's.

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[Farmhand]

ahah, with higher than 1.2 volts input a 100 Ohms base resistor is required, I think to decouple the transistor base from the logic gates... hmmmm
With a mosfet that is not an issue. The base resistor will probably reduce the rise ad fall times reducing peak voltages and also raise the lowest voltage it will run from.
Not sure I'll have to see. But at least now it will run fine with over 1.3 volts input.

I think it will light up 4 x 5 mm bright white LED's no probs with under 1 volt input. I don't have any blue or other 5 mm LED's.

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[Farmhand]

PCB Layout needs a redesign, (the PCB layout in post #63 is wrong, below picture is correct). now with the correction made to the traces the
jumper needs to go right around the resistors to the other side of them, so a redesign of the basic layout is in order.
I got confused with upside down parts and stuff. Glad I tested it out with a hand drawn bigger PCB, good to get the finer points ironed out.
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[Farmhand]

With 1 volt it lights up 4 x 5 mm LED's ok as the picture shows anyway. But at 0.8 volts it lights them up less than I would like, and
the power draw is more as well.
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[Farmhand]

One thing we can do with circuits that run on low voltage is use home made primary batteries and such contrivances for the power source.

I'm fairly confident I can construct a primary battery that will supply the circuit with enough power to run continuously for as long as the battery lasts,
which could be a long time depending on the size and type. I intend to try several different methods including the bi-metal coil battery.
Building a bi-metal coil battery is not as easy as it sounds so a simpler construction might be the better option for me.
I ordered some magnesium ribbon to experiment with for magnesium-carbon batteries. Going by my experiments zinc/steel-carbon
batteries I think the magnesium-carbon combination will work well enough and be simple enough to be practical.
The challenge come in making one small but with good enough output and long lasting enough to be useful.

For situations where a stationary device needs only a small continuous input or where a device needs higher powers only part of
the time a simple primary battery and circuit to boost it's output into a storage cell of a higher voltage could be useful for long term
very cheap source of power for many things, basically anything that will run from a battery.

So with that in mind I think i want a circuit to boost the initial low power cell output into a battery of 3 to 5 volts and the circuit should
be regulated so that it stops when the output battery is charged and restarts when the output battery gets used.

This would allow me to charge up capacitor powered torches real fast and without cranking. All I need do is primary battery
maintenance every now and then.

I could use any rechargeable battery or stack of rechargeable batteries for the output battery and simply use capacitors in a couple of torches.

The grid connected commercial equivalent would be a charge station that accepts a couple of torches containing supercapacitors,
when the torch runs low just put it in the "charge station" and its charged in a few seconds or a minute or two. No need to wait for
hours for the torch battery to recharge.

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