Joule Thief

[Light]

But not getting the HV.
OK, it useless; playing alone.
Good luck...

[Mk1]

@all

I made research on magnetic amplifier

Quote"
The mag amp is a "magnetic field" kind of amplifier and is of Class H type.

Visually a mag amp device may resemble a transformer but the operating principle is quite different from a transformer - essentially the mag amp is a saturable reactor. It makes use of magnetic saturation of the core, a non-linear property of a certain class of transformer cores. For controlled saturation characteristics the magnetic amplifier employs core materials that have been designed to have a specific B-H curve shape that is highly rectangular, in contrast to the slowly tapering B-H curve of softly saturating core materials that are often used in normal transformers.

The typical magnetic amplifier consists of two physically separate but similar transformer magnetic cores, each of which has two windings - a control winding and an AC winding. A small DC current from a low impedance source is fed into the series-connected control windings. An AC voltage is fed into one AC winding, with the other AC winding connected to the load. The AC windings may be connected either in series or in parallel, the configurations resulting in different types of mag amps. The amount of control current fed into the control winding sets the point in the AC winding waveform at which either core will saturate. In saturation, the AC winding on the saturated core will go from a high impedance state ("off") into a very low impedance state ("on") - that is, the control current controls at which voltage the mag amp switches "on".

A relatively small DC current on the control winding is able to control or switch large AC currents on the AC windings. This results in current amplification."

From http://en.wikipedia.org/wiki/Magnetic_amplifier

[xee2]

I tried a germanium transistor and I needed to change the base resistor to 50K in order to get it to work as well and the battery current went up to 4.6 mA. Germanium should be better since it will work from lower battery voltages, but this transistor does not work as well as the silicon transistor.

[xee2]

@ Light

I am primarily interested in high voltage also. But there are many areas to explore. For HV I suggest putting a step up transformer on the Fuji board output.

[jeanna]

Xee2,

I am curious about this. When MK1 first described this cap idea, I immediately stuck a .1uF cap in parallel with that base resistor, and the lights off the secondary went dim. They were still on, but barely. Then you made the response that the cap should have a low value to work in that spot.

I will use this as an exercise to understand caps a little better, so I want to be sure of my thinking.

Right now, I should find a lower value for the base resistor cap, and then add another one in what looks to me as across the battery. On the breadboard, that would be one pin in each battery strip.

That one can be a higher value. Yours is much higher than mine.

Also, please describe which type of capacitor to use in these places.

Thanks,

jeanna