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IGBT ZVS Induction Heater?

Among the many tutorials for building an induction heater out on the internet, there are two primary types. Some heaters use a ZVS circuit, and are quite simple but generally limited to a power of around 1000 watts, not enough to melt most metals. Other heaters use PLL controllers and coupling transformers to add charge the primary coil/capacitor loop, and these can be much more powerful but are significantly more complicated (and expensive) to build. It seems the limiting factor in the power of the ZVS circuits is that they can use only 2 MOSFETs, and each must conduct large amounts of current. However, if these could be replaced with IGBTs, which could conduct far more current, a much more powerful ZVS induction heater could be built. Is there any reason IGBTs couldn't be used for a ZVS heating circuit?

Topic by PleaseWork55    |  last reply


ZVS driver not working effecitently Answered

I have recently made a ZVS flyback driver. I got it working and the sparks are relatively impressive compared to other drivers I have made, but the arcs I'm getting seem a lot lower current and colder than pretty much every video I have seen of the ZVS driver. I used the Mazzilli ZVS schematic, and everything meets the specs in the schematic accept for the inductor which I made from a torroid i found in a PSU by winding about 15 turns of 18 gauge wire around it. the torroid has about a half inch outer diameter. I have a 5 5 primary on the transformer made from 18 awg wire. As it stands The driver is able to produce 20 to 25 kv with a thirty volt input, but the sparks are for the most part purple (not the flame like orange I have seem people get). As I didn't have any lead acid batteries around I just used six lantern batteries in series. I suspect the problem is either the power supply can't provide enough current, but I have measured and it seems to draw about 4 amps when arcing, and from what I understand it should draw about 10 amps and try to do that regardless of the power supply. I also think it could be the inductor is the problem, since it is what provides the constant current to the primary. If anyone knows what the problem could be and how to fix it, I would greatly appreciate your advice?

Question by Higgs Boson    |  last reply


ZVS Induction Heater help?

Hi, I tried to build a ZVS induction heater using this circuit http://img413.imageshack.us/img413/5136/inductionm.jpg , but I had no sucess. The work coil is 10+10 turns of 22 AWG wire around an old highlighter casing, and I am powering the circuit from a working 12 volt 7ah battery. The circuit works with my flyback transformer, but does not work on the induction heater. I am using all of the standard components in the flyback circuit, but I replaced the 5+5 turn primary with a 10+10 work coil. As far as I mesured with my thermometer the temperature of the object never increases over 1 degree (I am trying to heat copper wire or a small picture nail). Does anyone have some suggestions? Edit: Sorry about the delay, but I was able to heat a large paper clip using 8+8 turns of 16 AWG wire wrapped around a glass test tube. This time I used a huge 24 volt center tap 18 amp transformer to get 12 volts.

Question by TimTD    |  last reply


Power supply for ZVS driver?

I just built a beefed up ZVS driver to handle a large continuous current, however, I now lack a power supply that will allow me to reach its full potential. The biggest thing aside from my variac that I have is two xbox power supplies in series (24V 29A). I would like something around 40-50V with at least 5A. I could rewire a mot which would take a very long time and weigh a lot so if anyone has any schematics or pointers on how to make one electronically it would be much appreciated! 

Question by Jimmy Proton    |  last reply


70-100V powered ZVS?

So I was playing around with my ZVS driver and I turned up the variac to 40V, getting roughly 100kV and boom the flyback caught on fire and my ZVS driver fried. So I want to build a new one that could handle around 70-100V input. I know that for higher inputs some component values need to be changed but for voltages that high, I do not know exactly what would need to be changed. I was thinking of using two STY34NB50 MOTFET's, but wasn't sure if they were the right kind.

Question by Jimmy Proton    |  last reply


HV power supply and ZVS switching? Answered

I am slightly running out of brain power here and get the feeling I am just running around in circles. Problem: I want to build a HV power supply delivering 10-15KV that is driven by a ZVS circuit - basically the same I used in my Induction Heating Ible. I also want to double the output voltage with a simple cascade. Goal: To get the most effiency without overheating things. Areas where my brain feels too empty from thinking: 1. I know for sure the primary of the transformer will operate at a resonant frequency but how does this affect the scendary coil, especially under load? My small scale tests showed quite severe changes in the frequency depending on the load put onto the primary... Also the output voltage shows "spikes" at certain frequencies, I assume this happens while both primary and secondary share some harmonic frequencies. 2. With a simple dide/capacitor cascade I would only get a DC output, to keep an AC output slightly more complex circuits are required. How does this affect the resonant frequency of the secondary winding? 3. Considering 1 and 2, is there a simple way of keeping both the primary and the secondary coil of the transformer in resonance regardless of the load?

Question by Downunder35m    |  last reply


Connecting power supply to a zvs driver

Hi, can someone please tell me how to connect a power supply to a zvs driver. Thank you

Question by sadfiwnrsd    |  last reply


ZVS Driver purchased from Ebay

ZVS Driver should not be heated on the copper part until you put something from metal inside the copper ring, but this ZVS Driver heated the copper part without to put anything inside the copper ring! I want to ask is this correct to heated the copper part without to put anything inside the copper ring? Fans do not stop, working all the time! It something wrong with this ZVS Driver?

Question by Viktor Karadzhov    |  last reply



what is the turn ratio for a 220v to 36v transformer? Answered

I've a transformer core like a MOT(tall but slim) and i want to make a power supply for my zvs driver with it. so what should be the number of turns on the primary and the secondary if the input voltage is 220V AC and the required output is 36 v (min 10A). also what should be the gauge of the wires to be used for winding.

Question by jasshopper    |  last reply


Wireless energy transfer and resonant coupling?

I am getting a bit sick and tired of frying expensive parts, entire coils and sitting in stinking smoke for hours, so time to gather some new ideas from you guys ;) Problem as short as possible: I am working on wireless energy transmission. Not with the usualy distances we know from charging pads or electric toothbrushes though, I am aiming for 30cm and more of distance here. After endless hours wasted on testing different coil designs I think I got that one nailed quite good but the thing is that I seem to be unable to keep resonance under load. The coils require a very tiny window for the right operating frequency in the 40kHz range or for the other design in the 150kHz region. When the frequency shifts more than 3 or 4kHz from the resonant point the efficiency drops to useless. Since this entire thing is planned to be as simple as possible so everyone can do it I would like to prevent complicated electronics. The few I need so far are done through ready to use modules. Of course a microcontroller would be the most obvious choice here but that does not fit in as I like "old school" for this one. Two ways I considered so far with more or less success: a) Fixed frequency feed and limited output power. This works actually quite well but only allows for tiny power levels like charging a mobile phone or tablet if you have some time. Problem however is that load changes affect the frequency and without a link back to the sender the efficiency goes down and not enough energy reaches the receiver for usage. b) ZVS driven coil. So far this approach gives the best output power but also uses huge amounts of juice. Good to make a fancy glass stand for your TV and supply the power through a hidden receiver in the base of the TV but since there is no limit or link between sender and receiver it is full power only. Is there a really simple way to provide a limited amount of power together with automatic resonance keping? Next one might be a bit tricky: Is there a simple way to increase the harmonic frequencies? As we know every simple oscillator also creates and reacts to the corresponding harmonic frequencies. On the sender's side I would like to be able to not just feed the primary frequency but also one of the harmonic frequencies with a similar power level. Again without a microcontroller or extensive electronics where possible.

Question by Downunder35m    |  last reply


Input problem with OpAmp-controlled ZVS Induction Heater

Hello, Idea: I'm trying to build a circuit which uses an OpAmp to drive 2 mosfets, which power the LC tank of an induction heater. The idea is to detect when the voltage over the LC tank crosses zero, and at that voltage I would make the 2 outputs of the OpAmp change states from fully on, to fully off. The two OpAmps (both inside one chip) have their positive and negative inputs connected to eachother, but with reversed polarity. This would make sure that one output is high, and the other one is low. Why use an OpAmp? I wanted the MOSFET gate switching to go faster as usually, because in the mazzilli circuit, the gate voltage actually slews at the same rate as the LC tank's voltage slews when it crosses zero volts. In the mazzilli circuit, it actually doesn't switch when the voltage is 0v, but when the tank voltage drops below the gate threshold voltage. This would mean that you are always switching current at 5v (for example) instead of at 0V. So for these two reasons, I wanted to try switching them with an OpAmp. Measurements: Probe I on drain 1, probe II on drain 2, and GND on the circuit's ground, gives me an expected result: when switching states, at 0 voltage of the LC tank, the voltage on one side stays low (since it's pulled to ground) and the voltage on the other side goes from 0v up to 50v, back down to 0v, like a sine-wave. Then the OpAmps switch again, and the one side now goes up to 50v as a sine wave, and the other one stays low at 0v. All good, this is working just fine. Probe I on the one differential input line, probe II on the other differential input line. Since this is nothing more than just a 1/10 voltage division of the previous measurement, I'm also expecting the signal to be exactly the same, but 11x smaller. -> problem: However, this does not happen. Because of some strange reason, as you can see in the scope images: Both channels go high, Twice per cycle, instead of going high only once per cycle, and staying low for the next half of the cycle. This really isn't good! Do the inputs affect the waveform in some way? Remarks about scope images: Image: 2 gates Blue gate voltage seems 'quite' fine. Turning on looks good, turning off is not really good becuse if tends to turn on for a short time once again, before it fully turns off. Yellow gate voltage is terrible. Turning on doesn't happen as expected. Voltage drops back to 0 for a long while which is very bad for the circuit. Frequency seems fine; 50kHz is as expected with the 14µH and 6µF. Image: 2 drain voltages These voltages were measured with a 1-10 voltage divider, and thus show only 1/11th of the actual voltage. This is getting close to what I want the LC tank to do. The voltages seem quite like sine waves. I suspect that if the gate voltages would be as they should be, these drain voltages would also be perfect sine waves. The regular sine amplitude of 50V is as expected, with a 24V supply voltage, but at the moments when the drain voltages strangely drop down to 0v, as you can see in image: '2 gates', at these moments the drain voltage seems to spike over 250V!! Image: 2 differential input lines This is the image which I don't understand. I expect the same wave as in the previous picture, but only 11 times smaller because of the voltage divider. However, the voltage does NOT reach 0v while the drain voltage does, and its shape is also completely different. In this image, both channels are doing one (half) sine wave, twice per switching period. They should be LOW for half a period, as the drain voltages do in the previous image. Better quality images: 2 gates 2 drain voltages 2 differential input lines schematic Datasheets: OpAmp: http://cds.linear.com/docs/en/datasheet/1497f.pdf MOSFETS: http://www.vishay.com/docs/91262/91262.pdf Coils and capacitors: Line inductor value: I'm not sure if this value is correct. Center-tapped main coil inductance: This value should be pretty correct, I calculated it by measuring it's size and windings, and the operating frequency is also nearly the same as the calculated one. tank capacitance: 6 times a 1µf MKP capacitor Questions: - Why these strange large spikes? - Why is the waveform suddenly different when reading it near the differential inputs? For the first time ever, I can provide you with scope images! I finally bought a (quite cheap) oscilloscope. I hope it helps a lot. Oh, and one more thing: The induction heater does actually work already. I'm getting huge currents in the LC tank, since the 6mm copper tubing gets hot after a minute. Water cooling has been added, and it works like a charm! The MOSFETS do get quite hot after 15 seconds of heating an object, or after 40 seconds of heating nothing. This, probably because the gate voltage isn't what it should be. Kind regards, Electorials

Question by DELETED_Electorials    |  last reply


I'm willing to create a zvs induction heater but I have some questions Answered

Hello there! I want to create a ZVS induction heater but I don't fully understand yet how the coils need to be driven. I haven't started yet with building it, but I already wanted to check if the induction heating effect was working, so I connected a coil onto my high current DC blockwave generator and nothing really happens. it's a PWM controller which switches between 0V and the applied voltage. Is it because it sends DC signals to the coil, and the magnetic field goes into saturation? If so, I added a capacitor in series with the coil, to filter out the DC component but now nothing happens. There is nearly no current flowing trough the circuit. I'd also need some information on what influences the intensity of the heating? Is it the Amp*Turns that matters? because we're using high frequency here to lower the required current; but if it's amp*turns then we need the current to be as high as possible. So something's wrong there in the way I thought this works :/ I do know how the material gets heated. (by eddy currents that increase if the flux alternates at higher amplitudes) also, at what voltage should the coil be switched? does the voltage matter? Should I use something like 12v? 40v? or even 2v of I only need high current? I do know that the use of the high frequency is to increase skin effect in the material to be heated, but what other reasons are there for using such high frequency? Is it also because eddy currents will increase at higher frequency? If so, why would this happen? A lot of questions indeed :) but I'm not going to start copy-pasting the circuit, and then just being happy that it's working. I also need to know Why it works, and how! Thanks in advance, Electorials

Question by DELETED_Electorials    |  last reply


How to test N channel mosfets? Answered

Hello, i built a ZVS driver about an year ago. I used to power it from a computer power supply at 12v ,than i changed the power supply to 30v and 10a.With the new power supply it worked as well for about 3 moths. A week ago a wire got burnt and a zenner diode. I wanted to test the mosfets too but he tests i searched on google didnt work. Please tell me a good method to see if my mosfets are burnt or not .

Question by theVader75    |  last reply


Induction heater using the famous mazzilli vladimiro flyback driver?

After being done with 555oscillators and other hv projects. i am now interested with induction heater. i have seen multiple schematics on how to make them. However the parts needed are expensive. there was a similar question posted last year but did not have enough information etc. i have seen some people making the induction heater with the zvs driver of mazzilli, but did not give enough information on how to make it.  i need to wind 8+8turns on a flyback transformer core and 4 turns of thick wire one the other side to give more current. 1. can i wind the 8+8 turns on a toroidal core instead of a flyback transformer core(i don't want to break it even if i have more than 5) 2. for the capacitor 0.68uf. can a big 10uf 400v~ capacitor be used instead? or should i use 3X 0.22uf 400v~ in parallel so that it don't over heat due to high currents? 3. Will 2X 12v 35Ah car battery in series be enough to power the driver? i mean, will it drain the battery too fast which will lower its life span or should i use a rewound MOT?  4. Will a 2500uf 50v capacitor connected across the power supply be needed to smooth the current or will the circuit run finely without it.

Question by ARJOON    |  last reply



How to improve tesla coil ? Answered

I built a tesla coil, but the output is just a little spark barely visible when i approach a screwdriver to it. primary is 5 turns secondary 500t capacitor is made from 2 layden jars spark gap is about 3mm the coil is about 15cm tall the power supply is a flyback transformer driven by the zvs at 12v What do I have to do to improve it?

Question by theVader75    |  last reply


How to power tesla coil? Answered

I asked a similar question https://www.instructables.com/answers/How-to-improve-tesla-coil-/ and I still didn't managed to get a spark. I want the simplest way to build and power this tesla coil  Now I have : -5 layden jars -1 MMC -1 primary 5t -1sec 500t -1 zvs (dc out at 30kv) -1 ignition coil -5 timers -1 MOT -2 capacitors for MOT at 0.98uF -2 diodes for MOT

Question by theVader75    |  last reply


Cheap and portable >12V >10A PSU for small tesla coil? any good topload sugestions?

I am currently planning a small tesla coil (15 inches high, hopefully 5-12 inch sparks) I would like to make the unit small (desktop size). I decided to build the coil around a ZVS-driven flyback transformer rather than a standard NST or Oil burner transformer due to several advantages the ZVS circuit can offer: battery operation, smaller size, simpler math, no requirement to "match" the capacitance with the transformer, and since I have almost all the parts necessary to build another ZVS driver, why not!? The ZVS driver drive a DC flyback at approximately 15KV, which will then charge a homemade capacitor (I will not invest in a true MMC because it will put stress on the capacitors and connections, not mentioning the price of better quality film capacitors.) I have determined the dielectric breakdown of a few household items (plastic wrap, lids, lunch bags, etc. I assume they are low-density polyethylene) with my ZVS singing arc assumed to be at 8-10KV, and figured one layer of 5x7 inch compressed between 8 layers of plastic wrap gives an approximate capacitance of 0.7nF (sitting flat on a table with a few books to compress the plates closer together) to 1.44nF (after being rolled up very tightly. However, the breakdown voltage of this may be too low. I have yet to test this with my singing arc project)  The Capacitor will be several layers of plastic wrap sandwiched between layers of aluminum foil, which will be cut 3/4 inch shorter on all 4 sides, and after approximately 8-15 layers have been added, the capacitor will be sandwiched between 2 wooden boards with bolts on all 4 sides to permanently compress the capacitor to achieve approximately 10nF +- 5nF. This compression method might even help me fine-tune my tesla coil!  the aluminum plates will be tabbed, so that when they are stacked, the tabs will face opposite directions.  I might even submerge the capacitor in oil and pull a vacuum on it if I feel it will be necessary. However, I have not constructed a HV capacitor before, so I do not know how well this design will work. Does anyone have some experience in this matter? And lastly, my Power supply section to power the project: Has anyone built a ZVS-based tesla coil here? I see them all over youtube, with outputs ranging from millimeters (similar to my slayer exciter project)  to over a foot long! However, they never state what their PSU is rated for, or use 12 Lead Acid batteries, which I feel would be a bit impractical. So my question is: To get the output I desire, how many volts and amps should my power supply be rated for? I am thinking either a 24V 10A Switchmode supply from amazon, with the voltage adjust maxed out, or a 28V 10.8A SMPS, or a cheaper 24V 15A. SMPS. I thought about making a unregulated supply with a large transformer and a high-amperage full-wave bridge rectifier, but this cost more, and I cant be certain on it's quality. Can SMPS be used? can the amperage be below 10A? most importantly, does anyone have good data on current draw @ given voltages @ given # of turns on the inductor and flyback?

Question by -max-    |  last reply


How to power up a crt? Answered

I have a crt from a monitor and I want to power it how do i do that? I have its flyback connected to a zvs driver, and a computer power supply

Question by theVader75    |  last reply


can i up grade my zv5000 amd athlon processor to what maximum processor? Answered

I have a computer hp zv 5000, i want to up grade its athlon 1.6 processor, is it possible to upgrade to maximum what extent?

Question by hashmi121    |  last reply


Can I use are DC Flyback Transformer for tesla coil?

Can I use are DC Flyback Transformer for tesla coil? Just like a ZVS Flyback Driver If can please post the image. If not please explain

Question by james34602    |  last reply


Ball cyclotron powersupply? Answered

I'm planning on making a ball cyclotron as my project and i need a high voltage power supply for its working, can i use any type of high voltage power supply like a ZVS powered flyback transformer? Or is there any specific conditions for power supply to make the cyclotron work?

Question by jasshopper    |  last reply


Myler Capacitor for Tesla coil? Answered

http://www.electroncomponents.com/Mini-Components/capacitor/Polyester-Myler-Capacitors/105-400v-1uf-1000nf-myler-capacitor Is this good for a SGTC? im using a flyback transformer powered  with ZVS driver running of 30v. So im thinking of putting 60 of these is series and nothing in parallel. The secondary is 16inch long and 4 inch dia. Flat primary with 7 turns.

Question by jasshopper    |  last reply


How to square wave ---> triangle wave?

Currently I have developed a flyback driver that is a semi-cross between a classic ZVS circuit and a 555 type driver, mainly just using a few comparators (one to create a triangle wave and 2 others to respond to the upper and lower peaks and drive MOSFETs. This allows me to create a modified sine wave with adjustable duty cycle.) This topology is even more powerful than the ZVS driver at 12V, as I got some INSANELY thick arcs!! However the MOSFETs get a little too warm, and I was forced to use sil pads to galvanically isolate the drain from the CPU heatsink. They seem to have really poor thermal characteristics as the heatsink stays cold while the transistors get uncomfortably hot within seconds!! To make this thing operate at the resonant frequency of the flyback, I think I will a feedback coil that would get "squared up" using a resistor and zener diode. I need to convert that signal into a triangle / sawtooth wave of fixed amplitude. A simple RC type circuit is not too suitable because as the frequency goes up or down, the amplitude of the voltage across the capacitor changes proportionally.What circuit will allow me to convert a square wave directly to a triangle wave of fixed amplitude????

Question by -max-    |  last reply


Creating a handheld Emp device

Has anyone been able to create medium sized nonexplosive EMP generator? i recently purchased 4 oil capacitors each rated around 5.5KVDC and 32uF, from what i have learned, in order to create an EMP generator, you would need a to feed it a large amount of power in to  a heavy gauge magnetic coil. I believe my caps could do the trick. I will be charging them with a  ZVS driver coupled to a self wound ferrite transformer, then rectified. As for discharging i' will probably use a mechanical spark gap. I am hoping to create something like the shock pulse generators in amazing1.com, does my setup look feasible ?

Topic by tazerboy  


How to convert 300 volts DC to 30 volts DC?

Alright so i made a simple full bridge rectifier (http://www.electroboom.com/?p=544) credits to Medhi Sadahagar. I modified it such that it works with 240 volts mains instead of 120 volts mains. my capacitor bank is 2.4 mF and 400 volts. However, the output is 312 volts DC and I require around 12-36 volts DC at minimum 10 amps to power a ZVS driver (by Plasmana). I tried a voltage divider but I think the power rating of my resistors was not enough as one of them heated up and broke. I need help in designing or making a suitable circuit to reduce 312 volts DC to 12-36 volts DC at 10 amps minimum. Please help me and have a great day :D 

Question by BenderSanchez    |  last reply


Power supply from Ebay

I bought Switching power supply (220v AC>DC 0-48v DC 1000w 0-20Am)for my ZVS Driver, but not working properly, l need full 20Am, but this piece of shit do not given me more than 6.00Am at 50v! And values on the display are arbitrary!? I wrote on the seller for this problem, he wrote to me "When used load equipment The special insert must be taken out " I kill myself from 2 days to find this special insert, can't find it! Someone can tell me where to find this special insert? I post the full imal from the seller, he explains for knowing people, l need someone to explain to me with semple words / Dear friends The supplier replied that if you want to reach 20A, it depends on the actual current of the load. If the load is 6A, the maximum current can only be 6A. The actual current is determined by the load, and the actual current value is displayed. How to limit current: If no current is required when the current is limited, it is necessary to connect a plug to display the current value. The 6th and 7th connection port can be connected to a special plug to limit the current (regulate current). When using load equipment, The special insert must be taken out. When the load equipment is connected, the current value can be adjusted directly in real time. The maximum digital display current value is the maximum current value of the load equipment. Digital display current value will not have continuous real-time synchronous digital display, only the maximum current value of the device will be displayed./

Question by Viktor Karadzhov    |  last reply


Universal ultrasonic driver circuit - help required

I would like to build a few, properly working, ultrasonic devices.For example an ultrasonic soldering iron and an ultrasonic soldering bath.But some small ultrasonic plastic welder or cutter is nice too :)If you ever had one of the above to play with you know why they are great to have.The development story so far:I managed to destroy several driver boards.The ones you find for cheap with 28 or40kHz transducers in your favourite online store.In the beginning I knew I will have a need to repair or replace these boards but no clue why.Take an ultrasonic cleaner and read the manual.There it is always pointed out that a low water level can destroy your toy.What does that exactly mean?The transducer needs to be kept in resonance, if the water level is too low or something havy sits right at the bottom of the tank the frequency drifts off too much.Very expensive untis can cope a bit better here, which gave me the idea for the universal driver.During my experiments with hoorns I noticed that it is very hard to get usable results without extensive computer simulations first.Just one mm too long or too short and literally nothing happens, go a bit further and a thin aluminium horn might start to crack under the stress.And in all these cases the driver overloads, in one cheap case to the point that the transducer fused together.Trying to examine these driver circuits while they operate turned out to be a total nightmare!Place the probe from the ocsilloscope literally anywhere and the thing goes out of tune already.By the way: Never coil up the wires going to your transducer.....Only way I found that somehow works is by adding a tiny transformer around the wire going to the transducer and to measure the voltage generated there.To make it short: Destructive testing provided the requirements a driver needs to match to keep the cost low.Reasons for the premature death of cheap driver boards:Almost all of these cheap drivers I could find generate the 28 or 40kHz signal from the mains voltage.Means it goes through a transformer to get the desired 50-80V and some witchcraft turns that into a more or less smooth DC voltage.This is then switched by some beefy transistors, mosfets or similar, depending on the circuit.The actual feedback happens with a tiny ring toroid, similar to what you use to drive a ZVS system.With this dirt simple design a fully tuned transducer - like when nothing is attached to it yet - would cause the driver to provide a voltage of about 6x of what the transducer is rated for.Thankfully in most cases the transducer survives this a couple of times while the transistors fry within about 3 seconds no matter how good the cooling.Slightly out of tune - like when mounted onto a cleaning tank - the resonant frequency is slightly off the tuned 28 or 40kHz.The driver compensates this through the tiny feedback transformer.But this only goes for a about 1-4kHz, drift away further and first the power drops, then the voltage spikes and it dies.The feedback is not able to shift the generated frequency enough as it is ultimately derived from the mains frequency of your grid.Reasons why a dedicated, low cost driver would open new possibilities:Imagine you need to make a horn or sonotrode for your transducer.Knowing that each half of it should be equal to a quarter wavelength of the operating frequency is nice and easy.But if you add something like a blade for cutting or you need some pressure for welding then calculated dimensions become useless.Programs to fully simulate complex sonotrode designs, especially if you need to add screws or blades are costly and out of reach for most of us.Even if you would have access you still need to know the material properties to know the speed of sound in the material and how much it can flex in various directions without being subjected to metal fatigue.For basically all hobby needs in terms of ultrasonic gadgets we are happy with a simple push pull motion.the same motion our transducer offers by default.And when it comes to attachments it turned out that quite stubby horns of light weight are a good compromise already.A 50-50 ratio of diameter and length works reasonably well in most cases.For example the standard 40kHz transducer of 45mm diameter is quite happy to work with a horn like this:45mm diameter on the thick end, 20mm diameter on the tin end.Thick part 40mm long, thin part 42mm long.The extra 2mm are for the manual tuning by filing or sanding it off until there is good cavitation happening when you put the end into water.This however is only good for simple testing purposes and some fun but as soon as you attach blades or a small pot with about 200grams of molten solder the tuning is way off and destroys the driver quickly.To be able to deal with different pressure levels on the working end or just a different mass that is attached the driver needs to "know" the new self resonant frequency.Basic idea for a dedicated driver:Please bare with me on this one as my developing days got severly neglected once I moved to the other side of the globe....Input should from a 12V power supply, preferably a PSU to keep costs and sourcing time low.The operating voltage for the transducer shall come from a simple switch mode supply.I was thinking of scrapping a PSU for the transformer and switching transistor.This however would provide about 120-160V on 240V mains with the transformer of a PSU.To match the required load changes it would be great to drive this first transformer by PWM means to regulate the output voltage with a potentiometer while keeping it steady within the set values.Basically like every cheap phone charger but with an output voltage that can be adjusted and kept regulated.The switching transistors for the transducer should be well over the required specs of an out of tune transducer.I guess capable of switching 600V should be sufficient.Main design change to the cheap driver boards would be the feedback.A hall effect sensor could provide the proportional voltage to the current going into the transducer.It would also provide the real operating frequency of the transducer for the feedback loop.The resulting real resonant frequency of the running system is then used to drive the switching transistors.As a result the transducer would always be driven at the exact right frequency no matter the load on the working end.These transducers still have a quite limited frequncy range due to the fixed counterweight on the back - it is optimised to be self resonant without the transducer being mounted.To explain this feature let me use a spring with a weight on it....You can move your hand up and down to make the weight swing up an down with the spring force.You can also push the weight to get the same effect.But if the weight would just expand and contract there would be no change in the spring force or position or the weight.Our transducer however is mounted to something and the weight on the back is heavier than what is on the front end of the transducer.As a result the weight is pushed back and forth and because all is fixed together this movement is transfered to for example your cleaning bowl.Without anything attached to the transducer it would literally start to rip itself apart until either the bolt or the ceramics fail.The feedback loop needs to prevent this by adjusting the switching voltage going to the transducer.Once too far out the system needs to shut off until it can reset.The frequency control is not that fragile.With the power controlled through the feedback even a wide drift in the operating frequency of about 5kHz would only reduce the effectiveness and amplitude of the moving horn/sonotrode.Sadly my skill set in circuits is not that good anymore to have the required parts in my head and to know how to combine them properly :(Why this concept is only really good for really basic applications:Professional solutions utlise often less than 20W of ultrasonic power for a soldering iron or scaler.For these devices the sonotrode/horn is spefically designed for the task at hand.Same goes for any possible attachments - without them these things don't do much at all.Finding these low power ceramic transducer rings for a good price is hard enough, making an amplifying horn even harder.But when using these quite big 50 or 100W transducers we find for cheap online we can compensate the lower amplitude with the added power of the transducer.Since we only need surface action but won't have to go through a few liters of liquid it might even be beneficial.Fun fact: A 40kHz transducer has the second harminc frequency at about 170kHz.Means we could design a driver for the second harmonic and enjoy total silence when working with it.Would also mean that the ultrasonic power would be much higher.Mass times acceleration and such things ;)If you want some ultrasonic cutter then you don't want to waste weeks and lots of money trying to come up with a working attachment to your transducer.Just keep it as short as possible and with about the same weight as the front part of the transducer.At least the driver desing would make it quite easy to design an amplifying horn by trail and error through reducing the lenght of the thin end until it really fits.Anyone with good circuit skills willing to volunteer? ;)

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