thanks. today I build the coil from lidmotor video. I buying a new 13.56 mhz crystal but yet the circuit cannot be working the ferite rod nothing doing when insert it in coil.

erlandl,

are you sure your bottom lead of the 100K resistor is attached to the base (middle) leg of the transistor?   
On the pictures it looks like its attached to the ground/emitter part of the circuit.


Itsu

Hi Erfandl,

Would like to ask what is your indicator for seeing whether the oscillator works or not, with this new coil?

Do you have an AV diode plug connected to the free end of the air coil and the diodes feed a LED?
You can use such "sniffer" AV plug holding in your hand like Slider shows in his above picture. It should indicate also at the collector in itself if you touch the common diodes point of the AV plug to the collector.
Gyula

thanks gyula. Im do it and LED is turning on. but cannot turning an 4 watt LED like lidmotor

All,

i was looking into getting the x-tal oscillator to be able to supply over 20Vpp at 13.56Mhz.
I build the shown x-tal oscillator using a 13.56MHz x-tal and it works OK, then used the by
TK mentioned SN74AC14 to buffer/clean up the signal which shows a nice DC square wave like signal.

The problem however is to boost this 5Vpp 13.56MHz signal.
A normally used MOSFET driver will not cut it, my highspeed IXDN614CI works fine with a 4Mhz
X-tal, but fails to be stable at 13.56MHz (IXDN614 rise/fall times = 25/18ns).

RF version MOSFET drivers are very expensive.

Then i used a BJT totem pole setup as driver using BC547 and BC557 transistors and shows
promising results but when attaching a MOSFET (IRF840) the signal sags till some noisy ripples
unable to open the MOSFET.

So it will be a challenge to boost the 13.56MHz x-tal signal so its useable to drive the L3 coil
and CREE like leds board/diodes to full light.

Itsu

Hi Itsu,

I have pondered on this and the first thing would be to utilize resonant voltage increase of tuned LC circuits right already in the xtal oscillator itself as a first step.
I mean to place a tapped LC circuit into the collector of the xtal oscillator to step up the 13.56 MHz signal to as high as possible with such transformation.  See this LC circuit how I mean:
https://overunity.com/17249/dr-ronald-stiffler-sec-technology/msg522125/#msg522125  The oscillator circuit can remain the same you have now, just remove the 1 kOHm or the choke coil from the collector and insert the LC tank there.  The L coil here could be wound on an RF toroidal core you may have from Amidon to have high Q for the tank. 

Another possibility is to use the air core coil itself (called here as L3) to step up resonantly the 13.56 MHz collector current to a relatively 'high' voltage. See this sketch here:
https://overunity.com/17249/dr-ronald-stiffler-sec-technology/msg522451/#msg522451 
 What I mean here is this: coil wire #1 would go directly to supply voltage positive and coil tap #2 would go directly to the collector of the transistor. The air core coil should also resonate at 13.56 MHz,  basically this is very similar to the previous tapped LC tank suggestion, just the C is supplied by the air coil self capacitance and by the capacitive load the AV plug will represent with the LEDs too.  This latter 'autotransformer' is more difficult to tune to resonance than the LC tank on the toroid, due to the fully open L air coil.
If these resonant RF voltage up-transformer methods prove useless in the end, then we can ponder on further solutions...   
Gyula

Hi Erfandl,
Very good progress!  It is good to suspect the behaviour of choke coils and now you chose a good type for the job.  Some adjustments you can still make would be to use a 100k or 220 kOHm trimmer potmeter to replace the 100 kOhm base resistor and adjust for the best brightness possible by that too.   Make sure to connect at least a 10 kOhm resistor in series with the trimmer potmeter to prevent excess base current when the potmeter is approaching to the very low resistance values, ok?  Try to wrap up the transistor body into a heat sink like metal cylinder to help conduct heat away from it.

A question: I cannot see it clearly from your picture: Do you have a ferrite rod in the coil now?

Gyula
PS The battery symbol is lit on the display of your DMM, it needs changing soon.   

thanks. OK I will order the 100k and 220k trimmer for testing and share the result when received. yes I used ferrite rod in the coil. Unfortunately, I do not have an oscilloscope that measures the coil frequency if I had an oscilloscope, the result would be better than that   
eh I didn't even notice the battery symbol  thanks for reminder

You need not order both trimmer pots, only say the 220 kOhm and a 10 kOhm resistor you put in series with it.

Regarding the ferrite rod, I suggest to use more turns for the coil to make self inductance higher in itself so that the ferrite rod should not be needed to plug into the coil fully or even half way: just a little, say  only 2-3 mm to get the highest brigtness. I mention this because at 13-14 MHz, good quality ferrite material is needed, otherwise losses are inherently introduced into the coil and brightness suffers. Unless you are fully aware of your ferrite specifications, manufactured for the 10-20 MHz range. 

Gyula

OK thanks. Yes, I'm just 2mm of ferrite core into the coil not all.

Just another +1 of congrats erfandl..that must have been a frustrating journey.
But now, that light output is well worth it and surpasses my own efforts with the Dollar Tree bulb easily.
I need a different bulb 

thanks slider 
I test the lidmotor circuit from this video ( https://www.youtube.com/watch?v=tJhdZNIUOiI ) with 4 watt LEDs extracted from fillament light. the result is better than the first crystal circuit. the diodes is Germanium gold bonded AA119

voltage is 12 volt @ 51.5 mAh - 618mW

thanks to lidmotor and Gyula