Akula0083 Light No3 - Dual TL494

[MarkE]

Negative resistance is a behavior, a transfer function, of a circuit that is powered externally.  Negative resistance means that as the applied voltage increases the current decreases and as the applied voltage decreases, the current increases.  In order to perform stably in oscillators, circuits that exhibit negative resistance are typically combined with limiter circuits.  Once the amplitude builds up to a certain level, the limiter diverts energy non linearly to prevent the amplitude from building to the point that the circuits saturate.  A classic example that uses the non linear resistance of an incandescent bulb is the Wein bridge oscillator.

[JohnnBlade]

Hi All,

I have redrawn the circuit, and its the current circuit that i am using right now.

If you dont have the parts, just use any parts that come close to them.

The ferrite is a tv flyback ferrite.

Its also the circuit that makes the reverse ringing pattern

Build the circuit and lets share some more, and hopefully go to the next step.


Movie of current circuit and scope shot
http://youtu.be/8_Bal_7F06s


Greets JB

[JohnnBlade]

Btw, if i connect the D6 diode the reverse ringing goes away

So first fix the circuit without that D6, the reverse ringing shows also when loading load to the output, but for simple sake dont hook up any load to the output of the ferrite, and first get the same ringing pattern to comfirm this circuit.

Thnx!

Greets JB

[EMJunkie]

Negative resistance is a behavior, a transfer function, of a circuit that is powered externally.  Negative resistance means that as the applied voltage increases the current decreases and as the applied voltage decreases, the current increases.  In order to perform stably in oscillators, circuits that exhibit negative resistance are typically combined with limiter circuits.  Once the amplitude builds up to a certain level, the limiter diverts energy non linearly to prevent the amplitude from building to the point that the circuits saturate.  A classic example that uses the non linear resistance of an incandescent bulb is the Wein bridge oscillator.

This is right! Also, and importantly, one must take note of the Difference between Differential Negative Resistance and True Negative Resistance

Differential Negative Resistance: Current Never goes to or below Zero. Non Linear in its appearance.
True Negative Resistance: Current will go below Zero and theoretically can go well below Zero the more Current Drawn. Theorised to be Linear with Current Draw.

I did no see any signs of Negative Resistance in your scope shots.

Don't mix the two as they are quite obviously not the same and in fact not even similar! Its a confusing situation because most people, even scientists don't know the difference!

All the Best

  Chris

[d3x0r]

It's not negative resistance; it looks like negative resistance.
It could be qualified as negative resistance because there is already an existing signal that is being reinforced.... I guess...
the beware was beware of people that are going to jump on that bandwagon, because that's not really an important feature.