Joule Thief

[MrMag]

WVDC MEANS WORKING VOLTAGE D.C.

I am pretty sure that the LED lights due to the voltage spike on the JT.
As in all electrical circuits, when power is initially applied to the circuit there is a voltage spike. To prove this, look at a light bulb or vacuum tube filament and see what happens when you first apply power. You may also notice this surge when you turn on your TV or Stereo.

The reason the jt lights the LED is that you are applying power on and off very fast so that you get multiple spikes or surges in the circuit. It is the voltage that is lighting the LED's not the current. The same applies to the fugi circuits. The higher the voltage to the tube, the brighter the light.

I feel Jeanna is on the right path when she mentioned about looking for the highest output voltage with the lowest battery current drain.

[innovation_station]

WVDC MEANS WORKING VOLTAGE D.C.

I am pretty sure that the LED lights due to the voltage spike on the JT.
As in all electrical circuits, when power is initially applied to the circuit there is a voltage spike. To prove this, look at a light bulb or vacuum tube filament and see what happens when you first apply power. You may also notice this surge when you turn on your TV or Stereo.

The reason the jt lights the LED is that you are applying power on and off very fast so that you get multiple spikes or surges in the circuit. It is the voltage that is lighting the LED's not the current. The same applies to the fugi circuits. The higher the voltage to the tube, the brighter the light.

I feel Jeanna is on the right path when she mentioned about looking for the highest output voltage with the lowest battery current drain.

dont think it matters lol 

i want to use power and a lot of it 

ist

[jadaro2600]

@xee2,

What I meant by forward voltage wasn't the drop in voltage accrued during use - it's the amount of voltage that the diode can handle while 'switched on'.

And putting two diodes in series to gain twice the reverse voltage handling doesn't make sense to me ( But i'm no electrical engineer ) - not at least to gain reverse voltage tolerance.  It does, but it doesn't...  only considering voltage drops across multiple components in a circuit?  true / false?

@any,

Diodes have a power dissipation - I assume this is shorthand for how much voltage and current they can handle in their operation before destroying themselves?

Would the ACTUAL number with regard to this 'power dissipation' be obscured by the fact the conditions in the diode are in fluctuation?  In one direction there is current and voltage flowing, but in the other, there is nothing? ...trying to make sense of the 'power dissipation' is becoming interesting...

On the Vishay 1n4148 switching diode, the power dissipation is 500mW - meaning it could handle a wide range of voltage / ampere circumstances.   The max forward current on this same model is 500ma ... and I suppose that at that current it could only sustain 1 volt - which is equal to the voltage drop?!

@all,

Lets say, for instance, that we have two diodes of equal properties on the same line, in parallel so that current can flow through the line in either direction - wouldn't the reverse voltage on one be irrelevant - the diode essentially being protected from any breakdowns since the current and voltage would be flowing through the other diode?

[xee2]

@ jadaro2600

What I meant by forward voltage wasn't the drop in voltage accrued during use - it's the amount of voltage that the diode can handle while 'switched on'.

That is the reverse breakdown voltage. Putting two reverse biased diodes in series is just like putting two capacitors in series. In fact, a reverse biased diode is equivalent to a small series capacitor.

[TheNOP]

I am pretty sure that the LED lights due to the voltage spike on the JT.

if it was only due to the voltage, some peoples in here would not have problems lightning their troublesome leds.

As in all electrical circuits, when power is initially applied to the circuit there is a voltage spike. To prove this, look at a light bulb or vacuum tube filament and see what happens when you first apply power. You may also notice this surge when you turn on your TV or Stereo.

the name of this is "inrush current" http://en.wikipedia.org/wiki/Inrush_current

When a transformer is first energized a transient current up to 10 to 50 times larger than the rated transformer current can flow for several cycles. Toroid transformers can have up to 80 times larger inrush, because the remanent magnetism is nearly as high as the saturation magnetism at the "knee" of the hysteresis loop.

The same applies to the fugi circuits.

not exactly.
my kodak camera flashes rely on an oscilator, a step up transformer and an auto step up transformer to trigger the flash tube.
the oscilator is not a "blocking" type in my flash unit and the fuji one don't look like using one either.