Warning!

Building a HV supply is your own responsibility. High Voltage experiments are dangerous, and may hurt you, or even cause death to people using pacemakers, or having heart disease or any other heart weakness. If you know only few things about high voltage or electricity, and electronics, please ask for the help of a more skilled person. Be extremely careful. Though the lifters seem to be a very funny game, they are not! Consider it as real scientific experiments, and be as serious as you can to protect yourself and others in your house or "laboratory". Take care particularly of the children who could try to replicate your experiments when you're not at home. If you build a HV power supply, the risk of any results is just yours. I take no responsibility of anything that might happen.

Avertissement!

Construire une source de haute tension est votre propre responsabilité. Les expériences de haute tension sont dangereuses et peuvent vous blesser, ou même causer la mort de personnes utilisant des pacemakers, ayant des maladies de coeur ou simplement des faiblesses cardiaques. Si vous ne connaissez que peu de choses relativement à la haute tension, l'électricité ou l'électronique, demandez de l'aide à une personne plus compétente. Soyez extrêmement prudent. Bien que les lifters puissent sembler être des jouets amusants, ils ne le sont pas! Considérez-les comme des objets d'expériences scientifiques, et soyez aussi sérieux que vous le pouvez pour vous protéger vous-même et les autres personnes qui pourraient s'approcher de vos appareils chez vous ou dans votre "laboratoire". Faites particulièrement attention aux enfants qui pourraient essayer de reproduire vos expériences lorsque vous n'êtes pas à la maison. Si vous construisez votre source de haute tension, les risques qui en découlent vous concernent. Je n'endosse aucune responsabilité relativement à ce qui pourrait se passer.

To build a HV power supply, you will need:

- a DC power supply about 60-70v (batteries or an AC/DC transformer, powered from the mains)
- a TV or Computer monitor Fly Back Transformer (FBT)
- some electronic components to build a pulsing circuit which will transform your 60-70 Direct Current into a pulsing current (0 <--> 60-70v)

Note: according to your own power supply building, some components of the following circuits may be useless. For instance, I didn't need the 7812 voltage regulator, for I had already 12vDC from my power supply. This component is used to reduce the 16.8v voltage to 12v from the two batteries in the first circuit in this page, so that it can be correctly feed the timer NE555. If you are using a reliable DC source (powered from the mains), you may not need the C5 condenser 220uF. But if you are not sure it is a good DC sources, then keep it, for it will stabilize your DC source.

Reminder: this pulsed current is sent into the FBT, in a primary coil. The changes of the magnetic field in the primary coil (due to the pulsed current) will generate induced current in the secondary coil (which have much more turns to increase the voltage - the current will decrease at the same time). As there is a diod in the output of the FBT to straighten up the current, the latter is almost a DC one (I believe a perfect DC could be obtained with a condensor more than the diod, but here I am not an expert!). You will obtain a DC tension about 30 to 35kv.

It is necessary to place a resistor 150-250k 4-5w in case of short cut, if the lifter wires cross, so that you won't burn your transistor.

Electronic schemas

The two electronic circuits below are from Saviour at Blaze Lab (http://bel.150m.com/exp03.htm). The first one has been build by Jean Louis Naudin http://jnaudin.free.fr/html/lwhvps.htm, and the second by Saviour.

Please always check the orignal webpages of the schemas for the authors may have added some updates and new important advices.

Saviour, from Blaze Lab said :
"C5 is used to improve the capacity of the low power high voltage battery bank during each pulse. Your 200v cap should work. If you are using a mains powered dc source instead of batteries, you may not need this. "

Concerning the variable resistor 4.7k, I asked which value to use :
"The 4.7k adjustable varies the frequency, but most important, it also varies the output voltage. So, set this to say 1k, then switch on the circuit, and increase it until your output reaches 30kV [note: you can use a High Voltage Probe, and find some cheap ones at www.ebay.com - you can also build one by yourself, see the link page]. Note the circuit has been designed with lightweight as priority, and no circuit protections have been included. If you keep on turning the pot without monitoring your output, you may blow up your transistor. In my circuit, I used a battery bank of 100v, and got maximum voltage possible at 2.2k. I highly suggest the BU508DF transistor. There is nothing such as the best frequency, anyway it will be in the range of 16 - 25kHz."

Note: HR Diemen said that the FBT 7839's resonance frequency is 15625 Hz. So you can also use a frequency meter at the output of the NE555 (without connecting the FBT) and vary the 4.7k adjustable resistor until you reach this value. If you are using another FBT, try to find its diagram e at HR, and ask them the value of the frequency.

Another technical note from Saviour ( 04-05-02 ) - from the JLN webpage
"In the original design the transistor used was BU508D. The difference between this and a BU508A or BU208A is that it has a built in damper diode. If you use the 'A' versions, then connect a fast switching TV damper diode such as BY228 or BY448 across CE to protect the transistor against high reverse voltages. Without this diode the circuit may still work fine, as long as your lifter does not arc, but better be safe. I would prefer to use the plastic packaged (fully isolated) transistor (lighter and insulated) however if you have to work with the metal cased transistor make sure you insulate the case (collector) as this is connected to the high voltage dc supply. Note insulation in JLN's photo. Also, try not to leave any metal part of the circuit unconnected. In particular, the core of the transformer is preferable connected to the common 0v of the circuit. Just connect a short wire from the steel spring holding the core together, to 0v. Any unconnected metal may charge up to hv and at any time may discharge in the form of a spark to any part of your circuit. Also, remember that once your circuit is not connected to ground, the 0v is no longer at your body's potential, so it might not be pleasant to touch anything when switched on. Same applies to the lifter 0v."

BE CAREFUL, USE EXTREME CAUTION !!!, this device uses High Voltage, ALWAYS switch off the input and discharge the output to the ground through 10k/2W resistor before touch it. These plans are not intended for the inexperienced. User of this document should be very carefull and experienced in High-Voltage electronics to try anything out ! (...) JLN webpage

Click here to download the FBT HR-7839 diagram (pdf 12k)

The following one is from Blaze Electronics Lab http://bel.150m.com/exp03.htm ; it is a very lightweight one.

Design of lightweight hv supply for lifter

Extract from the webpage :
"Following various attempts to produce the best power to weight ratio hv power supply, my best present design utilises a colour tv line output transformer which has its driver circuitry built 'around it'. The below picture shows the power supply unit, that is battery operated. Weight is just 300g and power is approximately 80W at 45kV. Driver circuit consists of a 555 oscillator and BU508DF output transistor. Capable of running continously at full power without heatsink. Note the transformer is model HR 7493, others might need a higher dc input (>110v) to work properly, and will surely have different pin outs."

Click here to download the BU508DFI description (pdf 70k)

Now, the HV supply I've built :

I used a DC 68v powered from the mains AC220v/50Hz, (with the first circuit in this list) from an old amplifier I found in an electronic store. Then I bought the electronic components (I didn't want to use batteries, for they need to be charged regularly), and a FBT HR7839. The metal part of my AC/DC transformer 220AC/68vDC is connected to the ground. The 0v in the latter is also linked to the ground. I have two 0v/ground outputs in my AC/DC transformer. One for the 0v of the circuit, and another one to connect directly a discharge wand. The wand is made of an hollow insulated rod, with a plastic sphere (from a deodorant stick!) coated with aluminum tape. Then the lead comming from the inside of the wand is connected to the sphere. Once you have finished your experiment, switch off your power supply and pass the spere of the wand on the + lead. You'll see/hear a little spark. Then your FBT/lifter + pole is discharge and you can touch it. But please, read carefully all the safety guidelines given by Tim Ventura concerning high voltage experiments:

There is also a 150-250k 4-5w resistor between the HV+30/35kv and the positive lead of the lifter (see the drawing), so that a shortcut (thin enameled wires + and - of the lifter may cross during the experiment) won't burn the transistor. If you use a lower power, (i.e. 220k 2W), you resistor may burn. Then it will cut the circuit, which is good, but you'll have to change it after a too long shortcut.

Note: I have bought recently a High Voltage Probe Fluke 80k - 40kV on Ebay, for $37.85 (plus $17.35 for shipping to France, which is still a good deal!) on www.ebay.com and the measure of the output voltage of my FBT with the HV Probe plugged in a voltmeter is 30.4kV.

Cost :

Fly Back Transformer HR7839 : 39.5E
Electronic components: 20E
Power supply second hand: 30E
1 hour labour (to modify and refresh the power supply): 42.5E
Other components : solder, cables, plugs etc. : 18E
French Taxes (TVA 19.6%): 24.59E

Total: 150E (about $150)

Though their exists other ways to make high voltage supplies, and certainly less expensive, this one is working well and all the components may be found easily. Except maybe for the tranformer AC220v / DC68v-DC12v, which is old and a bit rare.

You can also order some high voltage supplies in the United States, at http://www.amazing1.com or even you can find some in the Ebay (bidding) website http://www.ebay.com from time to time. But you must not forget the taxes of your own country (TVA 19.6% in France) plus the customs (about 5-6%), and the mail price (it depends if you are in a hurry or not... international express and UPS are expensive, other means take weeks, and the cheapest - surface - sometimes months...). So that's why it's interesting to order from the US only if you have found a good deal and if the total price compared to what you could buy or build in your own country is less expensive.

By the way, don't forget that in the States the mains is 110v/60hz and in France 220/50hz. So you'll need to buy in your own european country a transformer 220/110v but you must ask to the seller if the apparatus will work in 50Hz!

But if you are skilled in electronics, then you will certainly save time and money!

So, this is a call for goodwill here: if someone is skilled enough in electronics, and would like to help to provide another cheapest way to build high voltages supplies (including DC supply powered from the mains (115v/60Hz U.S. and 220v50Hz Europe) needed in the circuit, that could be also plugged to a car battery for the outside), then welcome! The aim is to make easier the replication for all who are interested in. The best should be to use an easy to find power supply, like the one of a computer / and a car battery. The whole supply should have a potentiometer to vary the output tension, with a view-meter. The ideal should be to increase the voltage from 0 to 50kv or more (as well as the amperage for instance from 0 to 2mA or a little bit more) so that some heavier lifter models may be used to test various ways to increase the thrust, that could be reduced in weight later if they work.

Below, a request from a member of the JLN Group. If you would like to answer him, please email me and I'll forward the message :

"I will be happy to work with anyone who has a GOOD electronic circuit design background and can put or help put schematics on the WWW and will donate effective schematic for instruments that combine low cost and accuracy in reliable and stable measurement of:

-field
-gradient
-spatial specific field over a range of, about, 100 V to 75,000 V

This can then be posted on URL to experimenters.
NOTE: An Accurate design does NOT have to be overly complex or expensive, BUT, it must be a good design to combine such features.
Specialized design on request, example, UV, Ultra sonic, AC
fields, waveform, capacitance and inductance of given designs".

I hope all this will be useful and that you will succeed in the building of your HV supply as well as of your first lifter. To see it flying over the table is really amazing!

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