Transformer/Coil

[hevans1944]

My dear friend. We are not here to interrogate each other.

Not true. It is exactly why we are here. It is called a conversation.

For some obvious reasons I do not like the way you respond.

Obvious to you only. Remember, you came to us seeking answers. If you don't like our responses, take your business elsewhere.

I always have believed that the knowledge should be shared and the internet seems to be a fairly suitable media to serve the purpose.

We are more than happy to share our knowledge, but first we have to know how much you know.

I asked a technical question.

You first drew a circle with with some numbered dots and a larger dot labeled "stub" along with some sort of scribble in the middle. You probably thought this was meaningful, but I assure you it was not. Then you provided a schematic of a DC-DC converter with no apparent understanding of what that is. Then you asked "what difference does it make regarding the transistors"? Throw in tangent comments about MOSFETs and toroidal transformers and this all leads me to think you don't know much about electronics. In the software realm, I would call you a "script kiddy" but I don't think there is any comparable pejorative term in electronics for someone like you. In ham radio, you would be a "Lid" seriously in need of an "Elmer."

You either no the answer and willing to share it with me or you don't.

Well, duh! Of course someone here knows the answer, but they also need background information to properly answer the question. If you can't understand that... too bad. Go troll the internet for your answers.

I am not obliged to answer all your curiosities and the same way you are not under any obligation to answer mine. From the beginning your approach wasn't neither friendly nor appropriate. Why you should care where I've got the schematic from or what any other information would you possibly require!!!!!!!

It is a two-way street. You ask a question. We ask a question. You provide an answer, perhaps we provide an answer or ask another question to clarify what is going on. This forms a dialog, a conversation. You want to withhold information? Fine. Conversation ended.

I'll sort this out one way or another.
wish you a better social manner.

Fine with us. Please do.

 

[Kavin]

Dear gentlemen,

I apologize if my assumptions were incorrect. To the best of my knowledge I answered all of your concerns and questions. I am an electronics engineer and my area of work is microcontrollers. When it comes to power electronics, I'm lagging behind. As I explained earlier the output of this circuit is going to turn on a big flash tube like the ones used in cameras. The source of this schematic is google search. I also found out that I can use a step down transformer in reverse with 10 amp input which in return provides me with 1 amp output(correct me if I'm wrong). Obviously the more powerful output the better. Is there any other information I can provide you with?

 

[Arouse1973]

This looks like a Royer type oscillator so your going to need a core that saturates and one that has a narrow hysteresis.
Adam

 

[Kavin]

This looks like a Royer type oscillator so your going to need a core that saturates and one that has a narrow hysteresis.
Adam

Drar Arouse,

Thanks for dropping words. British manner. However, the reason I did not use the royer type oscillator is that royer type generates square wave in transmitter output, while I need a nice sine wave. I checked my circuit output and it has fairly a nice sine wave. Please let me know if I'm in the right direction.

 

[hevans1944]

... I am an electronics engineer and my area of work is microcontrollers. When it comes to power electronics, I'm lagging behind. As I explained earlier the output of this circuit is going to turn on a big flash tube like the ones used in cameras. ... Obviously the more powerful output the better. Is there any other information I can provide you with?

Thank you for that. Now we know we are not having a "conversation" with a rank amateur.

I, too, am an electrical engineer with experience in embedded microprocessor control and data acquisition... as well as power electronics and driving "photoflash" devices... among many other things. I don't profess to be an "expert" in anything, but all my life have sought to learn new things and teach others who are interested what I may have to offer. If that is a character flaw, I will continue to live with it.

I don't understand why you are adamant about sine-wave drive in the secondary. The secondary waveform is passed into a voltage tripling rectifier circuit and the DC energy stored on capacitors. The rectifiers and capacitors don't much care what the driving waveform is. On the other hand, perhaps your concern is harmonic interference if a sinusoidal waveform is not used?

Here is a web page that describes the 1954-patented Bright and Royer relaxation oscillator, modified further down the page for sinusoidal oscillation by adding a series LC circuit and substituting MOSFET power transistors, which of course did not exist in 1954. If you insist on sinusoidal waveforms, a toroid transformer could be an efficient choice if its core characteristics support the frequency of oscillation and it is large enough to support the power transferred. Note that very little power is consumed after the capacitors are fully charged, until they are discharged through the flash tube.

Your original sketch showed a pulse transformer (presumably) but provided no information on its characteristics. Is this something you have on hand that you hope will be suitable? Is there a part number or other identifying information available? Pulse transformers are not generally used for sinusoidal waveforms.

You stated your circuit will drive "a big flash tube like the ones used in cameras." This tells us nothing. Flash tubes cover a huge spectrum and so do cameras. How many joules per flash? Duration of light output in microseconds? Rise time required? Does it require synchronization to an event or a series of events?

You provided no information on how you intend to trigger your flash lamp(s). Connecting the charged capacitors to the flash lamp(s) by means of contacts on a relay is not advisable. The usual way to trigger a flash lamp is with a high-voltage pulse, either capacitive coupled to the tube, or by means of a pulse transformer in series with the flash tube, while the tube is connected to the charged capacitor(s) that provide the energy for the momentary flash discharge. Perhaps your relay is intended to be a safety disconnect to allow the flash lamp to be handled? If so, the normally-closed contact on a Form C relay (not a Form A as shown in your sketch) should be used to discharge the capacitor bank through a resistor.

For a specific design, a lot depends on exactly which flash tube(s) you plan to use. I would ask the manufacturer for information on how they recommend their flash tube be triggered. You also need to consider how often you need to trigger the flash tube and how much energy the tube will dissipate after triggering. These two factors will determine how much power your circuit must deliver, hence the supply voltage, transformer turns ratio and core composition, the transistor power ratings, and the output voltage and capacitor values needed. The flash tube manufacturer should be able to provide information on the hold-off voltage, the maximum discharge energy, the maximum pulse width, the maximum pulse repetition rate, and what cooling (if any) is needed.

Really large flash tubes require cooling, either forced air or by immersion in a circulating fluid with a heat exchanger and refrigerated cooling. For example, some solid-rod lasers are mounted in an elliptical cavity with the flash lamp at one focus and the laser rod at the other focus. De-ionized water, kerosene, and 3M Fluorinert FC-40 have all been used in the past for liquid cooling because they are non-conductive as well as transparent, but you are free to think of something else if liquid cooling is necessary. If operation in free air is your plan... then never mind.

Perhaps these questions mean nothing to you. Maybe they are irrelevant to what you are trying to do? If so, please pardon my intrusion.

 

[Kavin]

Thank you for that. Now we know we are not having a "conversation" with a rank amateur.

I, too, am an electrical engineer with experience in embedded microprocessor control and data acquisition... as well as power electronics and driving "photoflash" devices... among many other things. I don't profess to be an "expert" in anything, but all my life have sought to learn new things and teach others who are interested what I may have to offer. If that is a character flaw, I will continue to live with it.

I don't understand why you are adamant about sine-wave drive in the secondary. The secondary waveform is passed into a voltage tripling rectifier circuit and the DC energy stored on capacitors. The rectifiers and capacitors don't much care what the driving waveform is. On the other hand, perhaps your concern is harmonic interference if a sinusoidal waveform is not used?

Here is a web page that describes the 1954-patented Bright and Royer relaxation oscillator, modified further down the page for sinusoidal oscillation by adding a series LC circuit and substituting MOSFET power transistors, which of course did not exist in 1954. If you insist on sinusoidal waveforms, a toroid transformer could be an efficient choice if its core characteristics support the frequency of oscillation and it is large enough to support the power transferred. Note that very little power is consumed after the capacitors are fully charged, until they are discharged through the flash tube.

Your original sketch showed a pulse transformer (presumably) but provided no information on its characteristics. Is this something you have on hand that you hope will be suitable? Is there a part number or other identifying information available? Pulse transformers are not generally used for sinusoidal waveforms.

You stated your circuit will drive "a big flash tube like the ones used in cameras." This tells us nothing. Flash tubes cover a huge spectrum and so do cameras. How many joules per flash? Duration of light output in microseconds? Rise time required? Does it require synchronization to an event or a series of events?

You provided no information on how you intend to trigger your flash lamp(s). Connecting the charged capacitors to the flash lamp(s) by means of contacts on a relay is not advisable. The usual way to trigger a flash lamp is with a high-voltage pulse, either capacitive coupled to the tube, or by means of a pulse transformer in series with the flash tube, while the tube is connected to the charged capacitor(s) that provide the energy for the momentary flash discharge. Perhaps your relay is intended to be a safety disconnect to allow the flash lamp to be handled? If so, the normally-closed contact on a Form C relay (not a Form A as shown in your sketch) should be used to discharge the capacitor bank through a resistor.

For a specific design, a lot depends on exactly which flash tube(s) you plan to use. I would ask the manufacturer for information on how they recommend their flash tube be triggered. You also need to consider how often you need to trigger the flash tube and how much energy the tube will dissipate after triggering. These two factors will determine how much power your circuit must deliver, hence the supply voltage, transformer turns ratio and core composition, the transistor power ratings, and the output voltage and capacitor values needed. The flash tube manufacturer should be able to provide information on the hold-off voltage, the maximum discharge energy, the maximum pulse width, the maximum pulse repetition rate, and what cooling (if any) is needed.

Really large flash tubes require cooling, either forced air or by immersion in a circulating fluid with a heat exchanger and refrigerated cooling. For example, some solid-rod lasers are mounted in an elliptical cavity with the flash lamp at one focus and the laser rod at the other focus. De-ionized water, kerosene, and 3M Fluorinert FC-40 have all been used in the past for liquid cooling because they are non-conductive as well as transparent, but you are free to think of something else if liquid cooling is necessary. If operation in free air is your plan... then never mind.

Perhaps these questions mean nothing to you. Maybe they are irrelevant to what you are trying to do? If so, please pardon my intrusion.

Dear Hevans

Thanks or your enlightens. Your comprehensive explanations is most appreciated. Regarding the sine waves as you mentioned the harmonic interference is what I'm avoiding in the design I have in mind. I used the Royer type oscillator before and the result wasn't terribly satisfactory. Basically I've designed a few circuits recently to achieve what I have in mind but none of them was satisfactory enough and did not deliver what they were expected from. Therefore I did some google search and came up with the schematic we are discussing. It looked appropriate to what I needed so I ran it on my simulator which is SPICED base analogue simulator. The first part of the circuit looks fine but when it comes to the output of the transformer things are different. I ran a number of simulation and experienced with a number of transformers available to me and the outcome is different each time. The trouble I have is that in the original sketch no information has been provided regarding the transformer. This as absolutely frustrating. Last night I stayed late and constructed the first part of the circuit and used a toroidal transformer with ferrite
core. This is a 36-0-36v, 2 amp centre tap transformer with 115 input which I used in reverse. the output signal was fairly nice sine wave with a little distortion which I wouldn't be worried about. As far as I know my current at the output should be proportional to the input. I mean for example, let's say we have a 12 VA step-down transformer that takes 120Vac in and is rated to provide 12V at 1 amp at the secondary. If we were to reverse it and apply 12Vac to the new primary (the old secondary), we would have 120Vac at the new secondary, but to keep within the original ratings it could only be loaded to 0.1A @ 120Vac.
But in our circuit we have a step down transformer which has to 36v output . So when I'm doing my calculation shall I take the two 36v in series or parallel into account in order to find out about the current load. As if it should be calculated In series it only can be loaded in 1.6A @ 115Vac and if in parallel it would be 3.2A @ 115Vac.

Regarding the flash tube, I am not pretending to understand all of your comments, but I will definitely get in touch with the manufacturer before I place my order and will discuss my findings in this forum.

about the discharging the capacitors I have in mind to design a timer for the relay in order to discharge the capacitors into the flash tube. I haven't thought about the relay yet as my mind was occupied by the transformer confusion lately but I believe you are right about using Form C relay as it looks more appropriate. I'll do my homework regarding the relay and discuss my findings right here.

and finally, yes my tube will be free air running and as I mentioned earlier I'll definitely contact the manufacturer and certainly share my findings with you.

One more thing I have in mind is that I do not believe changing my transistors to more powerful ones is going to make a huge difference in the output as it is going through a transformer anyway. Or I'm missing something here. Last night I changed the original transistors with IRF520 and 2SC1969 (the most powerful available to me) but I couldn't see much improvement.

 

[hevans1944]

Your reasoning is correct about using transformers "backwards" from their original intent. However, this only applies under steady-state conditions. A flash-lamp power supply does not draw power continuously. Once the capacitor bank is charged, and before the lamp is triggered to discharge the capacitors, very little power is consumed.in the interim. What you need to be concerned about is how fast you want to charge the capacitor bank between flashes. This will determine how much power you must deliver to the charging circuit. Again, this is peak power consumed only during charging. The interval between flashes will determine the average power you need. Every photographer who uses electronic flash is aware of the annoying "wait and whine" between flashes. Some devices have very long waits and others have much shorter waits. It all depends on how much power the charging circuit can deliver to charge the capacitors between flashes.

It is theoretically possible to charge a capacitor bank to a voltage high enough to ionize, and thereby cause conduction, in a flash lamp as soon as that voltage is applied to the lamp. It appears you intend to do that with a pair of relay contacts connecting the capacitor bank to the flash lamp. This will probably work once, or maybe even twice, but it is not good practice. Once the flash-lamp begins conduction (a few hundred nanoseconds after the voltage is applied) the initial conduction streamer (a thin filament of ionized gas between the anode and cathode) rapidly expands because of impact ionization of gas molecules in the tube, driven by the high voltage between anode and cathode. This is a positive-feedback avalanche process that leads to a plasma arc in the tube, very high conductivity and a low voltage drop across the tube. The main thing limiting the discharge current is the inductance in the connecting wires and effective series inductance of the capacitors. Hundreds or even thousands of amperes of current flow for a few tens or hundreds of microseconds as the capacitor bank discharges through the flash lamp. This is not good for any relay contacts for which I am familiar. It is also something from which you will have to carefully protect your microprocessor circuits.

 

[Kavin]

Your reasoning is correct about using transformers "backwards" from their original intent. However, this only applies under steady-state conditions. A flash-lamp power supply does not draw power continuously. Once the capacitor bank is charged, and before the lamp is triggered to discharge the capacitors, very little power is consumed.in the interim. What you need to be concerned about is how fast you want to charge the capacitor bank between flashes. This will determine how much power you must deliver to the charging circuit. Again, this is peak power consumed only during charging. The interval between flashes will determine the average power you need. Every photographer who uses electronic flash is aware of the annoying "wait and whine" between flashes. Some devices have very long waits and others have much shorter waits. It all depends on how much power the charging circuit can deliver to charge the capacitors between flashes.

It is theoretically possible to charge a capacitor bank to a voltage high enough to ionize, and thereby cause conduction, in a flash lamp as soon as that voltage is applied to the lamp. It appears you intend to do that with a pair of relay contacts connecting the capacitor bank to the flash lamp. This will probably work once, or maybe even twice, but it is not good practice. Once the flash-lamp begins conduction (a few hundred nanoseconds after the voltage is applied) the initial conduction streamer (a thin filament of ionized gas between the anode and cathode) rapidly expands because of impact ionization of gas molecules in the tube, driven by the high voltage between anode and cathode. This is a positive-feedback avalanche process that leads to a plasma arc in the tube, very high conductivity and a low voltage drop across the tube. The main thing limiting the discharge current is the inductance in the connecting wires and effective series inductance of the capacitors. Hundreds or even thousands of amperes of current flow for a few tens or hundreds of microseconds as the capacitor bank discharges through the flash lamp. This is not good for any relay contacts for which I am familiar. It is also something from which you will have to carefully protect your microprocessor circuits.

Many thanks for the reply. The recharging time is what I'm concerned about when it comes to the output section of the circuit. As you mentioned the high current is needed in order to minimize charging time of the capacitors. based on my initial calculations the 10 to 14 Amp should be sufficient enough to shorten the recharging time to an acceptable time period. What is your opinion regarding this?
I also repeat my previous question. When I'm calculating the load current, shall I take the two 36V output of the transformer in series or in parallel into account ?

 

[Kavin]

Let me correct myself. 10 to 15 Amps in the primary side of the transformer (Initially secondary side) is what I meant.

 

[hevans1944]

Many thanks for the reply. The recharging time is what I'm concerned about when it comes to the output section of the circuit. As you mentioned the high current is needed in order to minimize charging time of the capacitors. based on my initial calculations the 10 to 14 Amp should be sufficient enough to shorten the recharging time to an acceptable time period. What is your opinion regarding this?

I have no informed opinion on this because you have not provided sufficient information, some of which i realize you may not have yet. For example, what calculations did you perform to determine that 10 to 14 A are sufficient to shorten the recharging time to an acceptable time period? As they say in school, please show your work.

Please specify the output voltage and the value of the energy storage capacitors (said values generally determined by flash lamp selection) so I can determine the amount of energy stored between flashes. Then tell me what an acceptable recharging time period is so I can guesstimate the current requirements.

If you have a manufacturer and a part number for the flash lamp, that would be helpful. Or maybe you could link or upload a datasheet for the flash lamp. There are literally thousands of different "camera type" flash lamps out there, many from Asia with little or no documentation, so sometimes you just have to "wing it" based on experience and perhaps some careful experiments. Or maybe you can copy a design that you know will work for you. Be aware that even "careful" experiments sometimes result in destruction of components, so it is a good idea to have a few spares on hand if you are going to experiment with your flash lamp. And wear eye protection when firing off that puppy.

Is 10 to 14 A the charging current for the capacitor bank or your expected input to the transformer primary? If this current is charging the capacitor bank, it sounds like a lot of current for a typical flash lamp capacitor bank: like, full charge in just a few milliseconds, implying a pretty fast flash repetition rate up to a kilohertz or so. Not a big deal; high-powered strobe lamps do this routinely, but it is a design factor. Again, these are important design parameters that only you can determine, based on what flash lamp you select and how you want to use it.

I also repeat my previous question. When I'm calculating the load current, shall I take the two 36V output of the transformer in series or in parallel into account ?

Your 36-0-36 V AC, center-tapped 2 A transformer can deliver its rated current to either half or both halves of the windings. The voltages, with respect to the center tap, are 180 degrees out of phase with each other and the current rating applies to the whole winding. There is no way to connect the windings in parallel. So, you can obtain 2 A whether you draw it from the entire winding (72 V AC) or with separate loads at 36 V AC from each half to the center-tap. In either case, the same 2 A is flowing in the secondary winding.

Assuming the primary was rated 115 V AC, the turns ratio for the secondary winding is 115:72 or 1.597:1 and the maximum current you can expect from the "primary" (operating as a secondary) is 2 A / 1.597 = 1.252 A when the "secondary" is driven with 72 V AC at 2 A.

 

[Kavin]

The capacitors C1,C2,C3 have the value of 1uf at 200v. Cx has the value of 10uf at 400v.
Regarding the flash tube I still am not sure. I've seen some but I haven't decided yet. The one I have in hand has some values on it but not clearly readable. I guess it is 4000W. If this is correct, knowing the output of the transformer after tripling is around 350v, so the 10 to 14 amp looks acceptable.

 

[Kavin]

There are two things which are troubling me. First of all am I obliged to use 36V? can't I use 12 Volts instead. I'm quite sure that I will be able to achieve the desired AC Output by 12V. Am I missing something here? The next Thing which may Sound funny is that what is the meaning of the word STUB on the drawing I posted in the beginning of this tread?

 

[davenn]

if you put a lower voltage in, you just get a lower voltage out

 

[hevans1944]

The capacitors C1,C2,C3 have the value of 1uf at 200v. Cx has the value of 10uf at 400v.

Those values seem to be on the low side except for a very small flash lamp such as you might find in a disposable camera. Take a look at this link for some typical photography flash lamps, capacitors, transformers, etc. I have no idea where the web site originates, perhaps Japan or Taiwan, but it is a place to start.

During flash lamp discharge, C1 is essentially in parallel with Cx, discharging through D1 and D3. The series-connected C2 and C3 are in parallel with C1 and Cx during discharge, so the effective capacitance for energy storage is Cx + C1 +[ (C2 x C3) / (C2 + C3)] or about 11.5 μF. If the output reaches a peak voltage of 350 V DC, the amount of energy available to the flash lamp is 1/2 CV² = 0.5 x 11.5 x 1E-6 x 350² = 0.704375 J = 0.7 watt x seconds.

A typical flash lamp discharge requires around 100 to 1000 μsec, so each discharge dissipates (during the flash) an instantaneous power from about 7043 watts (shorter pulse) to 704 watts (longer pulse). The average power depends on the flash repetition rate: P = Q (in joules) / period between pulses (seconds). Your circuit, pulsed at 100 flashes per second (period = 0.01 seconds), would only require about 70 watts.

Regarding the flash tube I still am not sure. I've seen some but I haven't decided yet. The one I have in hand has some values on it but not clearly readable. I guess it is 4000W. If this is correct, knowing the output of the transformer after tripling is around 350v, so the 10 to 14 amp looks acceptable.

All the flashlamp datasheets I have seen specify either a maximum energy per flash for photography or a maximum power and a maximum flash repetition rate for stroboscopic use. It is possible you do have a 4000W flashtube, but that would be one of the larger ones. Can you take a picture of it with a scale or ruler next to it to provide some idea of how big it is? Is this a linear flash tube? Does it have one or more trigger electrodes on the outside of the tube?

 

[hevans1944]

There are two things which are troubling me. First of all am I obliged to use 36V? can't I use 12 Volts instead. I'm quite sure that I will be able to achieve the desired AC Output by 12V. Am I missing something here? The next Thing which may Sound funny is that what is the meaning of the word STUB on the drawing I posted in the beginning of this tread?

I think you are free to pick whatever voltage you want. It all depends on the turns ratio of the transformer.

That stub may be a high-voltage insulated trigger electrode (if it is a conductor), but I don't see why the transformer would have so many "extra" wires if it is just a trigger transformer. I've seen this type of construction somewhere before but can't remember where or when or why it was used. There are lots of pictures on the web for all sorts of transformers, but I haven't found yours yet.

 

[duke37]

It seems as if you are wanting about 100W or so. You will need a fairly large and heavy transformer if you if you use a mains transformer. Incidentally, why 115V if you live in the UK?
I have never seen a ferrite cored mains transformer.

You can wind your own transformer using a TV line output transformer core. This could have 1 turn/volt so not a lot of turns. These were made to run amateur valve transmitters needing 300 and 800V. This would be run at over 10kHz to be above audio frequency. The weight and size would be low. Much higher frequency is used in such things as computer power supplies but things such as layout become critical.

If you use fets for efficiency, they must be driven fully on by a separate driver and the frequency must be above that which will cause saturation. You will get a square wave out which can be full wave rectified which needs little smoothing.

You may find information on suitable circuits if you look up capacitor discharge ignition systems.

 

[Kavin]

I think you are free to pick whatever voltage you want. It all depends on the turns ratio of the transformer.

That stub may be a high-voltage insulated trigger electrode (if it is a conductor), but I don't see why the transformer would have so many "extra" wires if it is just a trigger transformer. I've seen this type of construction somewhere before but can't remember where or when or why it was used. There are lots of pictures on the web for all sorts of transformers, but I haven't found yours yet.

I'll be working late until next Wednesday. Then the actual experiment begins. I'll keep you updated ans also take a photo from the tube and upload it in this tread.

 

[Kavin]

It seems as if you are wanting about 100W or so. You will need a fairly large and heavy transformer if you if you use a mains transformer. Incidentally, why 115V if you live in the UK?
I have never seen a ferrite cored mains transformer.

You can wind your own transformer using a TV line output transformer core. This could have 1 turn/volt so not a lot of turns. These were made to run amateur valve transmitters needing 300 and 800V. This would be run at over 10kHz to be above audio frequency. The weight and size would be low. Much higher frequency is used in such things as computer power supplies but things such as layout become critical.

If you use fets for efficiency, they must be driven fully on by a separate driver and the frequency must be above that which will cause saturation. You will get a square wave out which can be full wave rectified which needs little smoothing.

You may find information on suitable circuits if you look up capacitor discharge ignition systems.

Thanks for the reply. I do not live in the UK. At the moment I'm residing in Germany. But it wouldn't make any difference. They use 220v too but the point is I'm using the transformer in reverse so it is 115 volt output is what I'm interested in. 220v after being trippled would be to much for this experiment. At least that's what I think.

 

[duke37]

Using a transformer in reverse gives a low output because the transformer is designed to give a high output which drops to the design voltage under load, perhaps by 5%.

If the output voltage is too high, then use a doubler, not a tripler.

Edit. If you up the frequency, then you should be able to over voltage the transformer somewhat.

 

[hevans1944]

I am going to wait until @Kavin completes his experiments next week before offering any more comments. A hand on the oscilloscope probe is worth three pages of comments IMHO.

BTW @duke37, @Kavin wants sinusoidal excitation to avoid harmonic interference with associated microprocessor logic. This can be a real problem for mixed-signal designs involving analog signals and may affect digital signals too. If sinusoidal excitation is used much of the problem goes away, although there will still be considerable wide spectrum "noise" generated each time the flash lamp fires. Noise like this is suppressed by careful engineering design, including shielding where necessary.

Let @Kavin tackle those problems if or when they occur. Right now I would like to see him successfully power and trigger a flash lamp. These are "fun" devices to play with because you can see immediate results of success or failure. Also, for every engineering problem there are many solutions, some "better" than others. If the circuit does what it is supposed to do, my inclination is to stop there and go on to solve other problems. Over the years I have sometimes revisited "problems" that I "solved" in a not-so-professional manner. Sure, they worked, but I sometimes cringe when I think of what I might have done instead of what I did do. C'est le vie.

73 de AC8NS
Hop