Author Topic: STRENGTHENING GATE DRIVE SYSTEM( LONE OCEANS SSTC 4 )  (Read 642 times)

Offline prabhatkumar

  • High Voltage Experimenter
  • **
  • Posts: 81
  • Karma: +0/-0
    • View Profile
STRENGTHENING GATE DRIVE SYSTEM( LONE OCEANS SSTC 4 )
« on: June 15, 2020, 08:29:42 AM »
Hello there everyone. I have completed my first SSTC BUILD and it works reasonably well even at an input voltage of 130v DC. I have noticed and it has been pointed out by pothers in my other post, that my gate drive system is weak in the sense that it cannot maintain the climb without dropping a bit in the miller plateau. The drop is not very significant, but still I would like to make it better and strong enough so that the it can drive IGBT gates also at a voltage of about 15 volts or more. I do have a step up GDT with a ratio of almost 1:1.5, so that's a possible option also.
Now my first inspiration foe the SSTC was the LONE OCEANS SSTC2. Needless to say I went back to his website and found the full bridge sstc 4.
I have very limited parts at the moment and cannot order them also as even big sites like mouser are not shipping anywhere in my country due to lockdown. Neither can I order a ready made PCB from the factory. So only option with me is to do on a perfboard. I have a few tc4420, tc4427, DS0026, mosfet driver ICs which certainly cant supply the requisite current ( tc4420 might be able to do it as its 6A peak driver). I know many well why not using the popular UCC3732X  series. Well I used them before in my Sstc build but only to realize that the enable pins don't work, probably because they are rather cheap and Could buy 4 ICs for the price of one as compared with mouser. So now I think that its the fake ICs again that caused the slight weakening of the gate drive system. And also the entire purpose of using the UCC was the enable pins and also 9A peak drive current is not fulfilled.
So on going through the SSTC 4 of LONE OCEANS, i discovered he used gate drive strengthening system comprised of p channel and n channel fets.
LONE OCEANS SSTC 4 schematic:


Now many doubts which I want to get answered.
Firstly the choice of the FETS. He has used some FDS8958 dual N and P channel FETs. Now I dont have the dual channel FETs. I have also read on this forum (mostly it was Mads ) who advised to use the irf540 and irf9540 as a replacement. What i want to know is that is it neccesary for the FETs to be complementary of each other. Cant I use something like irlz44 and irf9540 just because I have them.

2) The next thing I want to know is whether is it possible to ICs like ds0026, tc4427 here. I Know they both are inverting but I will use 1 input of the hex inverter to invert the signal and feed it to the drivers. The reason I ask this that these ICs have 1.5 drive strength on each of the outputs. And Lone Oceans UCC27425 has a drive strength of 4 A. I think it should not matter much as we are anyway using the Fets to increase the drive strength.

EDIT: I was also going through The legendary driver UD1.3b of Steve Ward.
Steve wards schematic:

Also in Steve's design he used 2x10uF (C11 and C14 as dc blocking caps in parallel with a 10 ohm resistor to reduce ringing. The problem is that I understand that he used such big values so that gates of some chunky IGBTs could be run with ease, so can i reduce this capacitor value. I have some
3uF mylar caps probably and chunky 4.7uF film caps. I also dont have ceramic caps higher than 1uF.
picture of the 3uF cap:

I also came across Laci's post, reading through all the pages and then also saw that used a so called h bridge GDT driver based on ir2110 and irfz44. He said that results were good enough but certainly not the best due to ringing etc, and also that he lost quite many ir2110 ( reason still unknown), before finally giving up.
Post Link: https://highvoltageforum.net/index.php?topic=165.20

schematic for the h bridge GDT driver from the same post:

I think this schematic has a flaw, notice the high side of the bridge where there no bootstrap capacitors even no fast charging diode like uf4007, maybe that is the reason for his circuit failing.
Now I wont mind trying that method I am almost on the verge of completing the full bridge on ir2110, I have completed and checked the halfbridge section and it works fine I think. Only thing is that the ir2110 is drawing pretty good current like 120 mA and is getting hot. So please let me know if there is some error or is that the normal current draw by these ir2110 ICs.

Please answer my queries. Thanks in advance.
« Last Edit: June 15, 2020, 10:24:18 PM by prabhatkumar »

Offline davekni

  • High Voltage Engineer
  • ****
  • Posts: 449
  • Karma: +25/-0
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: STRENGTHENING GATE DRIVE SYSTEM( LONE OCEANS SSTC 4 )
« Reply #1 on: June 16, 2020, 12:19:22 AM »
1) Yes, many different PFET/NFET combinations will work for gate drive.

2) Yes, I expect most low-side gate driver chips will work for driving the FET pairs.  For these buffered designs, it would be ideal to do external enable gating, forcing the driver chip outputs high when disabled, leaving the discrete FET buffer stages clamped low.  With the SSTC4 schematic, the gate drive becomes floating a while after disable due to capacitive coupling to the PFET gates.

The GDT series cap size needs to be large compared to the IGBT total gate charge so that it will drop only ~1-2V charging all four gates.  It also needs to handle GDT magnetization current, which should be fairly small with a good GDT.  3uF is likely fine if your IGBT total gate charge is under 1uC.  The additional damping R/C is to minimize any series LC resonance of the coupling capacitor and GDT.  It likely isn't required in most cases, but could become an issue if the enable pattern happens to have a harmonic that hits the resonant frequency.

Yes, that last schematic appears to be missing boot-strap capacitors.

Ir2110 current should be mostly current required to charge the gates.  So reasonable current depends on gate charge and gate voltage.  120mA is about at that package's maximum power dissipation capability.  Perhaps you are using it to drive FETs that are larger or at higher frequency than is appropriate for that part.
David Knierim

Offline prabhatkumar

  • High Voltage Experimenter
  • **
  • Posts: 81
  • Karma: +0/-0
    • View Profile
Re: STRENGTHENING GATE DRIVE SYSTEM( LONE OCEANS SSTC 4 )
« Reply #2 on: June 16, 2020, 10:22:43 AM »
Thanks for the reply !!
I wanted to know the possible options for me. As much as I understand I think the p channel and n channel used should be complementary of each other. I wanted to know if this is true and why is is necessary for them to be complementary of each other.
At the moment I have got irf5210 and irf9540 for the p channel
And for the n channel I have got irlZ44n, irf3205, irf1010,  fdp3651u
Please tell me why do we need complementary FETs in this case and also if it is possible to pair any of the above mentioned FETs
Also regarding the ir2110 , I think the current draw is maybe optimum at 240 khz. My Chinese UCCs also drew around 280 mA (both UCCs) together when working in CW mode and at the same frequency.
UPDATE: The ir2110 circuit stopped working altother when i extended the half bridge to full brudge. Now the problem is even though there is no input given to the HIN pin, the output is still same has LOWOUT. Even if i give inverted signal to it, it still mimics the LOW OUT. God knows what is happening.
« Last Edit: June 17, 2020, 05:18:14 AM by prabhatkumar »

Offline davekni

  • High Voltage Engineer
  • ****
  • Posts: 449
  • Karma: +25/-0
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: STRENGTHENING GATE DRIVE SYSTEM( LONE OCEANS SSTC 4 )
« Reply #3 on: June 17, 2020, 08:01:35 PM »
Any combination of a PFET and an NFET from your list could work, depending on what driver chip is feeding the gates and on coil frequency and duty cycle.  Most of those parts have more current capability than needed.  That's fine in itself, but comes with higher gate charge.  Gate charge is supplied by the driver chip.  At 240kHz continuous, most of those parts might draw too much current and overheat the driver chip.  If you plan to run lower frequency and/or lower duty cycle as for typical DRSSTC use, driver power may be fine.  Of your two PFETs, IRF9540 has the lower gate charge and should be strong enough for even large IGBT bricks.  Of your NFETs, I think IRLZ44N has the lowest charge.  It also has a low gate threshold, which might cause shoot-through current with the PFET during switching.  (It's the only part that would work in the schematic using 5V gate drive.  Neither PFET is good at 5Vgs.)

It would be possible to use all NFETs for gate drive, but that would require a bootstrap gate driver IC to feed them.

120mA at 12V is 1.44W, at the upper end for IR2110.  That works only with good heat-sinking of the IR2110.
David Knierim

Offline prabhatkumar

  • High Voltage Experimenter
  • **
  • Posts: 81
  • Karma: +0/-0
    • View Profile
Re: STRENGTHENING GATE DRIVE SYSTEM( LONE OCEANS SSTC 4 )
« Reply #4 on: June 17, 2020, 10:13:14 PM »
Thanks for the reply !! I have got a partial success with irf540 and irf9540( yes I managed to find 3 irf540 from old box, they are new not salvaged and so are the irf9540).
I am able to get the intended -12 to +12 volt square wave now. I am using ds0026 instead of the UCC counterpart ( ucc27425). I had invert one of the signals with a cd40106. I am using my function generator as a signal source with 240khz frequency and a wave of 0-5v.
One issue which I am facing is that intended output square wave looks fine, but with a problem. The wave kind of begins to sloppy when it goes from 0 to -12v. I will upload the waveform soon for better understanding.
Also I couldn't understand why there will be a shoot through condition with the different fets(using irlZ44n and irf9540).
Maybe that sloppy wave is bit related to this.

Offline davekni

  • High Voltage Engineer
  • ****
  • Posts: 449
  • Karma: +25/-0
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: STRENGTHENING GATE DRIVE SYSTEM( LONE OCEANS SSTC 4 )
« Reply #5 on: June 18, 2020, 04:57:47 AM »
What voltage are you applying to the DS0026?  All of your FETs are specified at 10Vgs except IRLZ44N, which has on-resistance data at 4Vgs and 5Vgs.  Several designs use parts at 9V instead of 10V to reduce shoot-through, using drivers that swing the full output voltage.  Below 9V, the PFET may not turn on hard enough.  Above that, you may have shoot-through because the IRLZ44N turns on quickly while the PFET Vgs hasn't dropped enough for it to stop conducting.  It's not a mismatch issue so much as an issue of having the right gate drive voltage to make sure that each FET is fully turned-on, but is mostly off before the opposite FET turns on.  DS0026 doesn't swing quite the full supply voltage, so needs a bit higher supply to get the same output swing.
David Knierim

Offline prabhatkumar

  • High Voltage Experimenter
  • **
  • Posts: 81
  • Karma: +0/-0
    • View Profile
Re: STRENGTHENING GATE DRIVE SYSTEM( LONE OCEANS SSTC 4 )
« Reply #6 on: June 18, 2020, 09:11:36 AM »
Well maybe you are correct. Please have a look at the waveform attached.
Green is output of GDT, yellow is the output of the FET pair. Notice slight slopping nature of the waveform at the bottom end. And the ringing is there because there was no resistor in series to the GDT, only 3uF capacitor is there.


Green is the output of the function generator, notice it is collapsing, maybe the sloppiness is there due to this. I am adding a dedicated TLC555 to generate a square wave of 50 percent duty cycle to get around this function generator problem. Will update after being done.

Also can I power the DS0026 with 12 volt directly ? Its datsheet says upto 22 V, I guess doing that will fix many of the issues.
Update again :
There was quite significant effect of the Miller charge felt in that less than 5 volt drive. So I power the mosfet driver directly with 12 volts and then voila it started working only to realize that the mosfets started becoming smoking hot and the current draw was around 800 mA or more continuous.
And the waveform at the output was decent enough. Waveform at the output of the FET pair:


While running the circuit, i tried the following. I powered the mosfet pair with 24 volts and the gate driver circuitry by 12v. Now It draws around 1.2A. The thing which i realized is that the P channel FETs always got super hot while the N channel were still relatively cold. I am also attaching the waveform at the gates of one of the mosfet pair( capacitively coupled)

What i think is that the P channel high level is not zero volts but it is 1.3v. I think this is causing the issues. Please post your opinions on it and how can I fix it.
« Last Edit: June 19, 2020, 10:00:15 PM by prabhatkumar »

Offline davekni

  • High Voltage Engineer
  • ****
  • Posts: 449
  • Karma: +25/-0
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: STRENGTHENING GATE DRIVE SYSTEM( LONE OCEANS SSTC 4 )
« Reply #7 on: June 20, 2020, 12:44:25 AM »
DS0026 is an unusual chip designed for AC-coupled input.  It draws high (relative to normal logic) input current, 15mA if I recall correctly, more than a CD40106 is designed to drive.

Your function generator output does look odd.  What is your circuit and where is the function-generator connected?  It's amplitude looks too high for 5V logic.

Do you have the H-Bridge FETs or IGBTs (I forget what you are using) connected through a GDT to the buffer FETs?  If so, 800mA could be reasonable if you are driving large H-Bridge parts.  More likely it is shoot-through current, when both gate-drive FETs are conducting simultaneously.  The driver chip needs to output a clean square wave with fast rising and falling edges.  That way what shoot-through current exists is limited to very short periods of time.  If the driver chip output is sloppy, then shoot-through can last for relatively-long times at each transition, drawing excess power and overheating FETs.

If 12V is all you need for your GDT primary, then using the same voltage for the FETs and driver chip is fine.  If you need more GDT drive voltage, such as driving IGBT H-Bridge gates, then a separate higher-voltage (18-24V) supply is needed for the FETs.  (The IRLZ44N with it's low gate threshold will likely cause shoot-through issues if the driver output waveform is 0-12V.)

David Knierim

Offline prabhatkumar

  • High Voltage Experimenter
  • **
  • Posts: 81
  • Karma: +0/-0
    • View Profile
Re: STRENGTHENING GATE DRIVE SYSTEM( LONE OCEANS SSTC 4 )
« Reply #8 on: June 20, 2020, 05:54:25 AM »
I am using the standard irf540 and irf9540. And I realised it little late that ds0026 and apparently another driver which I had , MC34151 draw to high input current which the cd40106 cannot give.
I had no output attached to the circuit. Basically it was just the 2 FET pairs even without the GDT. Still the current draw became very high.
And I had updated my post later. And now the shoot through issue should be minimised reason being I am again giving 50 percent duty cycle signal from my function generator. And now there seems to be no issue with the input duty cycle.
Only thing is that I don't know the expected waveform at the gates .
Now after swapping the tc4427 for the ds0026, I realise that the current draw became very small again less than 90 mA at 12 volts input to the driver. I also swapped the irf540 for the irlZ44n I mentioned earlier. This made the circuit better. Probably there was heavy shoot through happening. With the tc4427 the rise time of the output was around 30 ns and with the ds0026 it was 15 ns. This, I think due to the slower rise time it creates bigger shoot through effect hence the mosfets get hotter. I probably will have to source the FETs in one package like the fdd8424 as the schematic of ud2.7. I am powering the driver with 9 volt and the FETs with 15 volt. I understand the output of the cd40106 cannot sustain at 5 volt ,it drops to 3.15 volt though still works for my case.  Now what happens is that even though I connect the GDT, current draw doesn't
increase at all.
Please check tell me what is wrong.
« Last Edit: June 20, 2020, 08:02:54 PM by prabhatkumar »

Offline davekni

  • High Voltage Engineer
  • ****
  • Posts: 449
  • Karma: +25/-0
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: STRENGTHENING GATE DRIVE SYSTEM( LONE OCEANS SSTC 4 )
« Reply #9 on: June 21, 2020, 12:20:44 AM »
 Irf540 and irf9540 should make a good pair, with little shoot-through using 9V on the driver.  Changing to IRLZ44N would increase shoot-through current.  So perhaps the excess current you saw has a different cause.  Not sure what other cause though.

A good GDT won't draw much current itself.  Its magnetization current is ideally 90 degrees out-of-phase with voltage, so not consuming any power.  The IGBT or FET gates on the output of the GDT will cause current to rise.
David Knierim

Offline prabhatkumar

  • High Voltage Experimenter
  • **
  • Posts: 81
  • Karma: +0/-0
    • View Profile
Re: STRENGTHENING GATE DRIVE SYSTEM( LONE OCEANS SSTC 4 )
« Reply #10 on: June 21, 2020, 05:02:00 AM »
I really dont know the cause, but now I will be using ds0026 only. I also had irlZ44n mosfet attached to the output of the GDT, still no extra current was being drawn. I checked the waveforms at the mosfet gate and it looked satisfactory.
« Last Edit: June 22, 2020, 03:13:27 PM by prabhatkumar »

Offline Mads Barnkob

  • Administrator
  • High Voltage Expert
  • *****
  • Posts: 1434
  • Karma: +24/-0
  • Denmark
    • View Profile
    • Kaizer Power Electronics
Re: STRENGTHENING GATE DRIVE SYSTEM( LONE OCEANS SSTC 4 )
« Reply #11 on: June 22, 2020, 10:25:24 AM »
Irf540 and irf9540 should make a good pair, with little shoot-through using 9V on the driver.

I have been using these in all my drivers and it has been running great. That said, I have not spent much time looking at the waveforms looking for tiny optimizations.
http://www.kaizerpowerelectronics.dk - Tesla coils, high voltage, pulse power, audio and general electronics
https://www.youtube.com/KaizerPowerElectronicsDk60/join - Please consider supporting the forum, websites and youtube channel!

Offline prabhatkumar

  • High Voltage Experimenter
  • **
  • Posts: 81
  • Karma: +0/-0
    • View Profile
looking for SSTC driver board
« Reply #12 on: June 22, 2020, 03:13:04 PM »
I agree with you mads. This design is trusted and tested by many. It might be my bad luck or something which I cannot understand. I have ordered few parts from aliexpress via DHL( very expensive, they charge customs like hell, but i have no other options but to pay it). There I have also ordered the fds8958 dual mosfet in one package which lone oceans used in is SSTC 4 board. Also can someone suggest me some boards to which I can order from pcb making companies. I am sick and tired of soldering on a perfboard and failing again and again.
I have found a really nice through hole pcb from profdc9:
https://github.com/profdc9/DRSSTC-PCB-Pack

I wanted to add a zero switching circuit also ( flip flop) so that later I can Use IGBT in a fullbridge configuration. So the ud2.7 through hole would be very nice to go, but there variety of other features like the over current protection which is not required in a SSTC. So can anyone help to basically omit the section which is not required in building a SSTC( except for the zero current switching). Sorry if I happen to break the forum rules of posting ( asking a straight forward question is mostly the case here).
I also want to add a musical interrupter now. I will be going with the interrupter from the kaizer power electronics website first. The only thing is that can someone tell me how and where to attach a optocoupler there to save my phone in case of any mishap.( I am at a very basic stage of electronics, Please even a rough drawn schematic would help me.)
« Last Edit: June 22, 2020, 03:17:30 PM by prabhatkumar »

Offline Mads Barnkob

  • Administrator
  • High Voltage Expert
  • *****
  • Posts: 1434
  • Karma: +24/-0
  • Denmark
    • View Profile
    • Kaizer Power Electronics
Re: looking for SSTC driver board
« Reply #13 on: June 22, 2020, 11:32:55 PM »
I agree with you mads. This design is trusted and tested by many. It might be my bad luck or something which I cannot understand. I have ordered few parts from aliexpress via DHL( very expensive, they charge customs like hell, but i have no other options but to pay it). There I have also ordered the fds8958 dual mosfet in one package which lone oceans used in is SSTC 4 board. Also can someone suggest me some boards to which I can order from pcb making companies. I am sick and tired of soldering on a perfboard and failing again and again.
I have found a really nice through hole pcb from profdc9:
https://github.com/profdc9/DRSSTC-PCB-Pack

ProfDC9 has a thread for those here: https://highvoltageforum.net/index.php?topic=353.0

I wanted to add a zero switching circuit also ( flip flop) so that later I can Use IGBT in a fullbridge configuration. So the ud2.7 through hole would be very nice to go, but there variety of other features like the over current protection which is not required in a SSTC. So can anyone help to basically omit the section which is not required in building a SSTC( except for the zero current switching). Sorry if I happen to break the forum rules of posting ( asking a straight forward question is mostly the case here).
I also want to add a musical interrupter now. I will be going with the interrupter from the kaizer power electronics website first. The only thing is that can someone tell me how and where to attach a optocoupler there to save my phone in case of any mishap.( I am at a very basic stage of electronics, Please even a rough drawn schematic would help me.)

http://kaizerpowerelectronics.dk/tesla-coils/musical-sstcdrsstc-interrupter/

The output just needs to be tied to a optical transmitter through a resistor, it is just a "LED", so choose a resistor to limit the current to whatever your transmitter LED uses.
http://www.kaizerpowerelectronics.dk - Tesla coils, high voltage, pulse power, audio and general electronics
https://www.youtube.com/KaizerPowerElectronicsDk60/join - Please consider supporting the forum, websites and youtube channel!

Offline prabhatkumar

  • High Voltage Experimenter
  • **
  • Posts: 81
  • Karma: +0/-0
    • View Profile
Re: STRENGTHENING GATE DRIVE SYSTEM( LONE OCEANS SSTC 4 )
« Reply #14 on: June 24, 2020, 05:22:23 PM »
Wow I just noticed someone else also had the same FET heating problem like mine. The source is the KAIZER DRSSTC1. I am attaching the screenshots for the same below. We got almost identical problems. Maybe if someone could help again.





High Voltage Forum

Re: STRENGTHENING GATE DRIVE SYSTEM( LONE OCEANS SSTC 4 )
« Reply #14 on: June 24, 2020, 05:22:23 PM »

 


* Recent Topics and Posts

post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
July 15, 2020, 09:35:15 PM
post Re: Seeking to build a 400+kHz IH, ZVS platform, high performance components
[Electronic Circuits]
JimOB
July 15, 2020, 04:11:45 PM
post Re: Seeking to build a 400+kHz IH, ZVS platform, high performance components
[Electronic Circuits]
JimOB
July 15, 2020, 04:10:39 PM
post Re: Seeking to build a 400+kHz IH, ZVS platform, high performance components
[Electronic Circuits]
johnf
July 15, 2020, 08:47:57 AM
post Re: Seeking to build a 400+kHz IH, ZVS platform, high performance components
[Electronic Circuits]
klugesmith
July 15, 2020, 07:56:14 AM
post Re: Little Bee B Field / Current Probe
[General Chat]
Weston
July 15, 2020, 02:25:42 AM
post Re: Seeking to build a 400+kHz IH, ZVS platform, high performance components
[Electronic Circuits]
T3sl4co1l
July 14, 2020, 11:33:09 PM
post Re: Different styles of HV electrodes
[Voltage Multipliers]
johnf
July 14, 2020, 09:48:39 PM
post Different styles of HV electrodes
[Voltage Multipliers]
MRMILSTAR
July 14, 2020, 09:34:39 PM
post Re: Little Bee B Field / Current Probe
[General Chat]
johnf
July 14, 2020, 09:19:11 PM
post Re: Little Bee B Field / Current Probe
[General Chat]
johnf
July 14, 2020, 09:06:21 PM
post Seeking to build a 400+kHz IH, ZVS platform, high performance components
[Electronic Circuits]
JimOB
July 14, 2020, 05:15:03 PM
post Re: Little Bee B Field / Current Probe
[General Chat]
Weston
July 14, 2020, 07:27:18 AM
post Re: Drsstc tank Cap testing
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Weston
July 14, 2020, 07:02:44 AM
post Drsstc tank Cap testing
[Dual Resonant Solid State Tesla coils (DRSSTC)]
oneKone
July 14, 2020, 05:56:46 AM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
July 14, 2020, 12:03:47 AM
post Re: Little Bee B Field / Current Probe
[General Chat]
station240
July 13, 2020, 01:08:35 PM
post Re: Server PSU Hack - HP DPS-800GB A, 12VDC 1000W
[Electronic Circuits]
rikkitikkitavi
July 13, 2020, 08:30:46 AM
post Re: Capacitors and arcs
[Beginners]
Paradox
July 13, 2020, 01:59:09 AM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
TMaxElectronics
July 13, 2020, 01:20:59 AM
post Re: compact midi interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
TMaxElectronics
July 12, 2020, 05:06:10 AM
post Re: Little Bee B Field / Current Probe
[General Chat]
Steve Ward
July 11, 2020, 10:23:24 PM
post Re: DRSSTC with litz-wire primary and 40 x TO247 IGBT H-Bridge
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
July 11, 2020, 09:36:02 PM
post Re: Server PSU Hack - HP DPS-800GB A, 12VDC 1000W
[Electronic Circuits]
Mads Barnkob
July 11, 2020, 07:36:23 PM
post Re: Server PSU Hack - HP DPS-800GB A, 12VDC 1000W
[Electronic Circuits]
Fumeaux
July 11, 2020, 04:45:18 PM
post Server PSU Hack - HP DPS-800GB A, 12VDC 1000W
[Electronic Circuits]
Mads Barnkob
July 11, 2020, 01:26:41 PM
post Re: Little Bee B Field / Current Probe
[General Chat]
Twospoons
July 11, 2020, 07:53:04 AM
post Little Bee B Field / Current Probe
[General Chat]
Weston
July 11, 2020, 06:37:03 AM
post Re: PCB etching, DIY (chemistry mostly)
[Printed Circuit Board]
klugesmith
July 11, 2020, 04:18:29 AM
post Re: PCB etching, DIY (chemistry mostly)
[Printed Circuit Board]
Twospoons
July 11, 2020, 01:35:07 AM
post Re: PCB etching, DIY (chemistry mostly)
[Printed Circuit Board]
klugesmith
July 10, 2020, 11:35:05 PM
post Re: Capacitors and arcs
[Beginners]
Morvandium
July 10, 2020, 11:10:57 PM
post Re: PCB etching, DIY (chemistry mostly)
[Printed Circuit Board]
Morvandium
July 10, 2020, 11:06:07 PM
post Re: Capacitors and arcs
[Beginners]
k42
July 10, 2020, 08:53:06 PM
post Re: XRay Tank- any ideas about what is inside
[Transformer (Ferrite Core)]
HighVoltageRulezz
July 10, 2020, 07:20:48 PM
post Re: Why is Auto-transformer (variac) called transformer??
[Beginners]
Morvandium
July 10, 2020, 04:45:43 PM
post Re: Cathodes in Compact Fluorescent Lamps
[Light, Lasers and Optics]
T3sl4co1l
July 10, 2020, 10:57:29 AM
post Re: Configuration of a half bridge.
[Electronic Circuits]
hammertone
July 10, 2020, 08:55:30 AM
post Re: Configuration of a half bridge.
[Electronic Circuits]
johnf
July 10, 2020, 08:48:33 AM
post Re: Cathodes in Compact Fluorescent Lamps
[Light, Lasers and Optics]
davekni
July 10, 2020, 07:00:13 AM
post Re: Configuration of a half bridge.
[Electronic Circuits]
davekni
July 10, 2020, 06:57:36 AM
post Re: Measuring LED efficiency
[Light, Lasers and Optics]
davekni
July 10, 2020, 05:44:54 AM
post Re: Configuration of a half bridge.
[Electronic Circuits]
johnf
July 09, 2020, 09:23:38 PM
post Re: Easy to build Polyphonic MIDI Interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
Max
July 09, 2020, 09:09:08 PM
post Re: Cathodes in Compact Fluorescent Lamps
[Light, Lasers and Optics]
klugesmith
July 09, 2020, 07:00:49 PM
post Re: Measuring LED efficiency
[Light, Lasers and Optics]
TMaxElectronics
July 09, 2020, 02:33:38 PM
post Re: Configuration of a half bridge.
[Electronic Circuits]
hammertone
July 09, 2020, 12:16:32 PM
post Re: Configuration of a half bridge.
[Electronic Circuits]
hammertone
July 09, 2020, 11:46:10 AM
post Re: Measuring LED efficiency
[Light, Lasers and Optics]
Twospoons
July 09, 2020, 10:56:18 AM
post Re: Configuration of a half bridge.
[Electronic Circuits]
johnf
July 09, 2020, 08:37:52 AM

Sitemap 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 
SimplePortal 2.3.6 © 2008-2014, SimplePortal