Toroidal Coils

[d3x0r]

is usually used with sine waves.
You are also experiencing coil loading. This is where the inductance of one coil is effected by coupling to another coil. Capacitive loading is also possible.


I think you have made the circuit so complicated that it is hard to understand. Perhaps experimenting with a simple series LC circuit made by putting a simple coil in series with a capacitor on the sig gen output would make things clearer.

Actually I'm mostly just using a signal generator a coil (or pair) and the LED load.... just considering ways to use more power... the signal generator is just an output from some semiconductor chip of unknown capacitance and unknown current. 


But earlier I was the pulse generator and a couple higher power transistors; and that was a square wave on the input and the output (well a sharp pulse anyway); and was non resonant; but had the equivalent increase in voltage that I get with a lower power resonant frequency.....




I guess the ground side doesn't matter on the recieving coil; if it's a seperate coil that has the ground...


The second image; test schematic represents the 2-coupled trifilar-bifilar coil test that the ferrite in the center of the toroid doesn't help...


the third image test schematic 2 is what my bench currently has, I get some 15V out, 3V in, 3Mhz, ground only on the second (outer); shorted winding important, but I can also just extend the primary winding to be both in a continouous path and that also helps...

[xee2]

This is a simple 2 transistor driver for square waves that worked for me:
http://www.youtube.com/watch?v=0KOTqPIqe1o


Be sure to use the output capacitor if you build it.

[d3x0r]

This is a simple 2 transistor driver for square waves that worked for me:
http://www.youtube.com/watch?v=0KOTqPIqe1o


Be sure to use the output capacitor if you build it.

Okay; that is a simple mod to my existing driver module; but I could only get 5V between Q1 and Q2....


running simulation, it's limited to the gate voltage of the NPN; unless the collector voltage is lower than that.  As the capacitor charges, the emitter voltage becomes higher; which makes its ground reference 5v=0... (something like that)

[xee2]

Okay; that is a simple mod to my existing driver module; but I could only get 5V between Q1 and Q2....


running simulation, it's limited to the gate voltage of the NPN; unless the collector voltage is lower than that.  As the capacitor charges, the emitter voltage becomes higher; which makes its ground reference 5v=0... (something like that)

I like the circuit because it only draws current from +V when charging the capacitor. As the capacitor is charged and discharged the current flows back and forth through the transformer primary thus providing an AC input to the transformer.

[d3x0r]

4th time's the charm; doesn't like attaching lots of files today.


Animated view of coil....

http://www.youtube.com/watch?v=OpC5Z6zMlD4

Contracting the coil reduces inductance some, but increases the output voltage.