High voltage experiments: Part 2- Homemade flyback transformer.

As i ve said before, in this second part i will show you my high voltage experiment using my own hand-wound homemade flyback transformer using the ferrite core from the original flyback transformer salvaged from old cathode ray tube (CRT) television monitor.

Before I move on, here are the photos taken and descriptions:

The overall setup. I ve changed the power supply from stacks of battery into regulated laptop power supply (indicated by black wire on the left) that can safely adapt power from the mains for project purpose. It supplies 9VDC at 3.16 A. I ve been using same inverter circuit i ve always been using before, except that for R3 i use 500 ohm, R1 at 3kOhm, and 10k potentiometer for R2 for easily varying the operating frequency ( pin 7 of 555 is connected to swiper, pin 8 to one of the end pin while the other end pin is left unconnected, so this potentiometer is modified into varistor rather than potential divider). Also to protect the mosfet i ve put a snubber diode 1N4148 in series with 464kOhm resistor, across the primary winding of the transformer, between the supply line and the mosfet's drain pin.

Closer look on the circuit. I use copper heatsink ( the finned chunk of brownish thing) for protecting mosfet from overheating.

Closer look on the left side.

Closer look on my homemade handmade flyback transformer

This is the original flyback transformer from old CRT tv monitor.

...and this is how the double C ferrite cores are dismantled from the transformer.

The primary winding. I made it to be fitted enough into core. First I take an old pamphlet paper ( since its not too hard) then i rolled it around the core, and I retained the cylindrical shape of the rolled paper using common tape. Then over the cylinder, i rolled one layer of PVC tape, and the purple wire. I added another layer of common tape so the purple wire coils firmly positioned on the red PVC tape. Notice i ve used 15 turns, but its up to you to use any number of turns as its only affects the amount of current u 'll get on the secondary.

Bird eyes view of the primary

The secondary coil. Same method with the primary ( also made to be well fitted on the cylindrical structure of the ferrite core), except that i used 25SWG ( about 0.5mm diameter enamelled copper wire) for the winding, with about between 30 to 40 turns per layer, and i ve had about 10-12 layers for that ( I dont quite remember), so there are about 350 to 400 turns overall. I am still using PVC tape and common tape for each layer. More on this design of secondary can be found here.

Bird eyes view of the secondary.

The components ready for assembly.

And it really works...

See ya next time.

p/s: after several times using the power supply, the 555 chip was damaged and i have to replace with new one. This maybe due to high current surge since i m using 3.16 A. Therefore I recommend you to put resistor (for example 500 ohm) between the supply line and any direct input from the supply into the 555 ( pin 4 and 8). To date, i connect pin 4 and 8 together, and link the node to the supply with a 500 ohm resistor. Though the spark becomes shorter, this method may prolong the 555 lifespan and u may still have fun with the spark.

High voltage experiments: Part 1- Flyback transformer

I admit that i am a very detailed learner and experimenter, who appreciate the fundamentals more than going straight to the target or subject i want to study. Thats why, you will see several experiments before i move on to making my own version of Tesla coil.

One of them that i ve been planning is two high voltage experiments using flyback transformer; one is salvaged from old television ( part 1, which is this entry) and one made by myself ( the ensuing part 2)

Flyback transformer is a special resonant transformer invented to generate high voltage, high frequency current. This transformer is mostly used to control the horizontal deflection system in any visual devices such as television and pc that are using CRT or cathode ray tube. That is why if you want it, as an alternative to buying from retailer or internet, u can also salvage it from old aforementioned stuffs.

Nowadays, its getting harder and harder to find old television and pc that has this kind of transformer since most of nowadays tv and pc are using LCD screen, so flyback transformer has no market at all ( msot companies stop producing CRT-based tv and pc from 2010 onwards, see wikipedia). Therefore, if u manage to get one, value it! I was so lucky yesterday when i was wandering around the rag market in the town searching for a used television, an old man was having it and sold it to me for about 10 pound. Besides flyback transformers, I also got other useful components for my other projects from the old tv such as speaker, electronic components and the second-most wanted stuff: the cathode ray tube ( so I can play with high freq voltage on it!)

By using the previously outlined circuit that used battery charger transformer to get sparks , i just substituted the transformer with the flyback transformer I got from the old tv. The pinout of the transformer is as follows:

Source: http://www.inpharmix.com/jps/Buzz%20Coil%20Flyback%20HV%20Generator.html

I got longer blue/purple sparks between the electrodes of the transformer's secondary, which is between 1cm to 3cm. Since my multimeter could not load high voltage thus i just reckoned that the voltage is about between 10 to 20 kV. Here are the photos taken:

Overall setup. The battery pack is actually 12V, there are other five cells under the three. The black bulky object with medium length fat wire is the so called flyback transformer. The fat wire is the outlet of high volt high freq current. Notice there is a 10k potentiometer. I substitute it for R2 in the 555 timer inverter diagram before. There is also heatsink where the MOSFET is attached to ( MOSFET cant be seen in the photo). The purple wire stretching out from beneath the transformer is the ground of the hi volt outlet. Please ignore the yellow wire in the picture,including the one wound on the transformer.

Purple wire is lengthen ( using additioal wire, thin yellow wire in the photo, now ignore the thick yellow wire wound on the transformer) to a spark gap, where the fat wire is also attached to its other end. The black rod is just fix the fat wire and the spark gap wire together and serves no other purposes. Two thin yellow wires from beneath the transformer are linking it to the main circuit on the breadboard.
Two medium size wires from the upper part of the transformer are not used.

Ready for experiment.

Closer look on the spark gap, where the spark will be observed.

and here are them:

Next post will be using my homemade flyback and better kind of power supply for more powerful spark.

My baby Tesla coil.

I started building Tesla coil by first learning how to build an inverter from DC supply. I found an inverter circuit here made by Joshua D. Wyatt, from this link.

There, he used the inverter circuit to power EL backlights and fluorescent tubes, so the output is about 127 VAC as he claimed. But I want 1kV or more to make at least 1mm purple plasma as Tesla coil usually produce! (30kV is required to make 1cm length plasma). Therefore i use MOSFET IRF 840 as a transistor for high switching rate (also any IRF-named MOSFET will do, such as IRF741 and 630) and also transformer i use before from cracking open a battery charger to step up the voltage to more than 1kV.

Here goes the schematic with specifications following it:

I used:

R1: 100kOhm. Again up to you. Its values controls the duty cycle of the triangular pulses generated at the end of the MOSFET.
R2: 464kOhm or more, up to you ( you experiment it yourself). This resistor controls the frequency so different values produce different sound pitches of the plasma ( it produces buzzing sound depending on its operating frequency)
R3:5.5kOhm
C1:0.047 microFarad
C2:0.01 microFarad
C3:0.1 microFarad
C4:100 microFarad
Q1: MOSFET transistor N-channel IRF840
T1: step down transformer from battery charger (converting 240AC to 2.8DC). For this project I inverted its function as a step up transformer.

The plasma length is about 2mm maximum, with the output voltage of about 1888V (I think it should be slightly higher since my multimeter couldnt measure it due to its limit...it almost broken and internal red light was seen flashing inside! I dont know where the light came from,there is no warning LED there, but my multimeter still survived that thrilling incident).

Here are the photos taken:

Just showing the transformer and red leads ( the plasma producing leads). I hate the circuit since it looks messy on the breadboard ( i hate soldering my projects...haha

The spark is very small, like i said before its 2mm in length. So small, and purple in colour. Cuz this is my 'baby' project before moving into the main one ( i m waiting for my copper wire to arrive to create my own flyback transformer)

Another photo from same angle, booooriiinnggg....

OK, gotta sleep now...bye

LM386 is godsend.

LM386 is very fun. It is a multi-purpose power amplifier 8 pin chip designed to amplify small power. I ve used it to amplify small signal from my crystal radio receiver and it works marvelously! It can even power up an 8 ohm speaker, to the sound level of mobile phone speaker.

This amazing chip i bought from Ebay for GBP 3.17 , and got ten of them. To use it as crystal radio amplifier, just Google the circuit schematic. I ve used the following schematic from techlib.com.

source: http://www.techlib.com/electronics/audioamps.html

Is LM386 only amplifying audio signal?? Nope. Like i said in first line, it is a MULTI PURPOSE POWER AMPLIFIER. Therefore, I deduced if I can amplify sawtooth signals generated from ubiquitous 555 DC pulse generator chip (another chip, not to be confused with LM 386), and further amplifying the resulting pulses with transformer, then I can get high frequency, high voltage, low current alternating current. Lets see...

The overall view. At the very left is the 12V DC battery power supply. Note two chips on the breadboard. The first one is 555 timer while the second one on the right side is the so called LM386. At the very right lies the so called transformer. I cracked open a battery charger to get this transformer, which its original role is to convert 240V AC current from mains to about 2.8V DC for battery charging purpose. I inverted its role as a step up transformer, by connecting its secondary to the circuit on the board. By applying 12V to the circuit ( where 4.3V goes to the primary of the transformer that linked to the circuit), I got 183V, 66mA alternating current at the very end of the transformer's secondary ( the red wire at the end of the transformer, see the magnified view below).

The close look on the transformer. The red ends are carrying high voltage between them (183 VAC), high frequency (about 200Hz) low current (66mA). When you touch it, you will feel a zap, but more pleasant and less painful than conventional shocking pen. I touched it many times becuz it felt great. :P

What amazed me the most about the high voltage high frequency current circuit above is that when I touch the two red ends, I felt the same impulse i ve got when I touched the shocking pen few years before but less painful and more fun. Back then, I wondered how did the shocking pen (shown by my friend to me) can gave such a very painful shock, now i manage to build the circuit myself! Haha. But poorly, this big circuit never ever fit any pen. Maybe its miniaturization will become my next project.

The ensuing photos explains more than words can do...

The circuit...actually the LM386 parts ( the power amplifier circuit) is just the one being depicted before. The 555 part can be Googled anywhere, it generates spike signals. I used spike signals rather than square or sinusoid since spike gives more intense impulse to our fingers. :D

The overall circuit. I dont know how to rotate it, you do it yourself.:P

Next project, small Tesla coil. Gotta work, see me in the next post.

RF as weapons.

RF (radio frequency) has many applications since its discovery by German physicist Heinrich Hertz (19th century).

Nowadays, its application is innumerable. We use RF to transmit and receive audio and video signals in wireless telecommunications, as detection means in military thru radar application, an also for household applications such as microwave cooking.

As i m moving into my private research from the start of this summer holiday, i am also researching into RF. My vision is to utilize Rf as weapon against gang-violence and gang bang.

This idea stemmed from a film I watched before. Its a science fiction film where there was a part where one of the character introduces RF when he was surrounded by the enemies, paralysing them temporarily for preset time interval while he remained immortal due to special gadjet he wore on his ears.

I am taking that part of the film seriously as an idea to develop RF weapon, especially for woman who has to walk alone at night and exposed to various gang crime such as gang rape, or just to benefit anyone whether u are man or woman from gang assaults.

Apart from that, I have also gained an idea few years before from a story told by my friend when he watched a pokie machine ( a type of slot machine usually depicting the characters from pokemon series) . He said to his friend ( while i was listening to them) that he felt somewhat sleepy after watching the lights ( notably red and purple lights ) flashing alternately in front of him from the pokie machine.

Again, I took this story seriously as an idea. I bet that alternately changing electromagnetic wave ( light is also electromagnetic wave as concluded by James Clerk Maxwell), or by generalizing it, alternately changing frequency of RF can be used as a mean to manipulate the enemies cognitive function.

However, i am still researching the method to immortalize ourselve from the RF while weakening our enemies with that. I hope by the end of this summer i will come to a fruitful solution.

And btw, Nikola Tesla from his research had succesfully produced a sleep-inducing machine, which i see as an encouragement that RF (or electromagnetic wave) is indeed useful as cognitive-manipulating weapon.

My first working radio.

Just the picture of a crystal radio successfully made by myself. It manages to capture several UK channels, most notably BBC Radio 4 and Absolute Radio. For this project I used enameled copper wire BS6811 (British Standard) for the inductor coil, a Schottky barrier diode 1N5817, an a Taiwanese-made crystal earphone. The schematic of the circuit is not fancy at all; you just type in 'crystal radio' in wikipedia, scroll down to the last line and there is the simple schematic i ve been using.

By successfully producing a working radio, i have accomplished one thing in my long list -to-do-before-I-die: Making a radio. Enjoy the pictures.Its not my final destination; instead its just a start to my arduous journey into the world of electronics.

The overall picture of the radio set. The coil is of utmost importance in this invention since it forms a tuner circuit with stray capacitor ( the wire and surrounding air) and the fixed capacitor ( the blue component explained below)

The circuit. Blue component is fixed ceramic capacitor. Its optional.

The breadboard where i plant all the components. The black diode is not an ordinary diode; it is called Schottky diode. Bought it from Maplin for less than 1 pound ( got 3 of it)

A crystal earphone. This earpiece has a very low internal resistance; hence reflecting its capability of detecting small signal compared to its ordinary counterparts. I bought it from Ebay with about 2-3 pounds ( dont quite remember).

Zoom out view.

Though this radio is going well with crystal earpiece, it doesnt mean i cant use an ordinary Iphone earpiece. If the signal received is strong enuf (happens occasionally, depends on luck) you can use ordinary earpiece with a little press into your ear. Only one side of the earpiece will produce sound since the signal is mono.


Update (13 June 2012): I repeated the crystal radio design and I managed to record the AM signal received. Here is the video. I am still using the same coil with LM386 audio amplifier.The sound was in fact, louder than u will listen from the video.