Author Topic: Gate waveform question  (Read 502 times)

Offline flyingperson23

  • High Voltage Enthusiast
  • *
  • Posts: 19
  • Karma: +0/-1
    • View Profile
Gate waveform question
« on: July 23, 2022, 07:49:57 PM »
Hey, I have my bridge assembled. I did a low bus voltage test and got the attached waveform across the igbt gates. Is there something wrong with this? If so, any ideas on how to fix it?

Offline Mike

  • High Voltage Enthusiast
  • *
  • Posts: 25
  • Karma: +2/-0
    • View Profile
Re: Gate waveform question
« Reply #1 on: July 24, 2022, 01:44:37 AM »
Something is very wrong but I'm struggling to figure out what. Your scope is showing peaks of more than 40V on the gate (if it's set up correctly) which is way too high. Also the duty cycle is very low, it should be 50%. You're zoomed out in time way too far to see what's actually going on, you should be looking at a time scale comparable to the period of your primary oscillation frequency, I'm not sure what that is for your coil, but probably closer to 10us/div.

Finally, what's your test set up? Is it low voltage on your full coil and driver, or are you just testing the bridge with a function generator?

Mike

Offline AstRii

  • High Voltage Technician
  • ***
  • Posts: 181
  • Karma: +6/-0
  • Czech Technical University in Prague
    • View Profile
    • UHVlab - Tesla Coils | High Voltage | Education
Re: Gate waveform question
« Reply #2 on: July 24, 2022, 02:41:42 AM »
When you say you tested the bridge, may we know how? Did you applied low voltage to the bus and tested it with a load? If so, can you measure the output of the bridge?
This waveform is absolutely wrong, but if the bridge "works" it may be a broken probe or disconnected ground.
Marek Novotny
Czech Republic, Czech Technical University in Prague
www.uhvlab.org

Online davekni

  • High Voltage Expert
  • ******
  • Posts: 1707
  • Karma: +86/-0
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: Gate waveform question
« Reply #3 on: July 24, 2022, 04:15:16 AM »
I'm guessing that the 750Hz repeat rate is your interrupter frequency.  Recommend testing at much lower interrupter frequency (ideally 1-10Hz) to minimize chances of frying circuitry.  Also start with short interrupter pulse widths, a few cycles worth, for the same reason.  Once things are working correctly, increase duty cycle.

Until gate waveforms and bridge output waveforms look correct, I suggest continuing with signal-generator replacing feedback CT input.  Your scope includes signal generator capability.  I have the same model.  A bit of a pain to use while scoping too, but possible.  Or stay with your external one.  Either way, duty cycle needs to be closer to 50% than in your previous signal-generator waveforms.  Low duty cycle is likely due to low signal-generator output amplitude.  Higher may not be possible with either signal generator.  To work at low amplitudes, change to square-wave output.  Doesn't match real CT signal, but should provide 50% duty cycle.  Square wave is fine (except for adjusting phase lead, which is better to do later with real CT feedback).

Thank you for posting waveforms.  As has been mentioned, more information helps.  State explicitly where scope is connected (ie. ground clip to low-side emitter and probe to gate), what supply is feeding H-bridge (ie. 12V from a bench supply or ...), etc.  Pictures of your build also help, especially if pictures show probe connection(s).  For signals such as in this post, multiple scope captures at different horizontal time/division are needed in order to interpret.  One as shown with several interrupt pulses, and at least one more covering the enable duration of a single interrupt pulse.  If looking at switching glitches, yet another zoomed in to show the glitch or ring of concern.
David Knierim

Offline flyingperson23

  • High Voltage Enthusiast
  • *
  • Posts: 19
  • Karma: +0/-1
    • View Profile
Re: Gate waveform question
« Reply #4 on: July 25, 2022, 05:18:07 PM »
I have a full bridge of cm300s, which I'm feeding low voltage and getting an output of a few dozen amps. Attached are a few pictures of my setup. Measuring one of the transistors with the emitter at scope ground gets me the attached waveforms. It looks decent and is interrupting at the ~80khz that I'm putting in as a feedback signal, but there are still pretty high voltage spikes and I don't know if that's the general shape it's supposed to take.

Offline flyingperson23

  • High Voltage Enthusiast
  • *
  • Posts: 19
  • Karma: +0/-1
    • View Profile
Re: Gate waveform question
« Reply #5 on: July 26, 2022, 01:46:12 AM »
I realized I should probably disconnect the gdt from the gate before measuring the output - after doing that I got these relatively clean square waves - do they look good?

Offline Mike

  • High Voltage Enthusiast
  • *
  • Posts: 25
  • Karma: +2/-0
    • View Profile
Re: Gate waveform question
« Reply #6 on: July 26, 2022, 03:10:06 AM »
GDT waveforms look good.

The overshoot that you're seeing on the gate is probably the inductance of the leads from the CT resonating with the gate capacitance of your IGBTs. Gate capacitance is fixed, you can't do much about that, so anything you can do to reduce the GDT output inductance (shorten the wires, ensure all leads are tightly twisted, etc) will help. It also looks like you're using a 0.1R gate resistor, I'm not an expert on these larger brick IGBTs at all but would have expected this to be closer to 10R. The gate resistor will damp the ringing during turn on at least.

Mike

Online davekni

  • High Voltage Expert
  • ******
  • Posts: 1707
  • Karma: +86/-0
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: Gate waveform question
« Reply #7 on: July 26, 2022, 04:24:36 AM »
Quote
The overshoot that you're seeing on the gate is probably the inductance of the leads from the CT resonating with the gate capacitance of your IGBTs. Gate capacitance is fixed, you can't do much about that, so anything you can do to reduce the GDT output inductance (shorten the wires, ensure all leads are tightly twisted, etc) will help. It also looks like you're using a 0.1R gate resistor, I'm not an expert on these larger brick IGBTs at all but would have expected this to be closer to 10R. The gate resistor will damp the ringing during turn on at least.
Yes, I agree with above.  However I'd thought you were using 5.1ohm (5R1) gate resistors.  If using 0.1, that explains the rising-edge overshoot.  Looking at the ring, I'd guess that about 5 ohms would be ideal.  (Even faster horizontal scale is good for looking at switching edges, at least down to 1us/div.)  If you already have 5R1 resistors, then higher would help, unless GDT/lead parasitic inductance can be significantly reduced.
Negative overshoot (undershoot) is worse because diodes bypass gate resistors.  Some designs add smaller resistors (say 2 ohms) in series with diodes to reduce undershoot some.  Many designs use TVS diodes instead of zener diodes.  TVS diodes are roughly the same as zener diodes.  (Both are actually avalanche-breakdown, not truly zener.)  TVS diodes are designed to handle much higher peak current.  Clearly your 30V zener diodes aren't clamping undershoot effectively given -40V scope peaks.  Also, TVS diodes come in bidirectional versions, having the back-to-back pair internally in a single package, generally for the same price as unidirectional versions.

BTW, I see what appears to be a circuit breaker on the DC bus.  It does not appear to be a DC-rated breaker.  Normal AC breakers usually don't work well on DC.  Might be OK, however, if between rectifier bridge and bulk caps.  That would provide zero-voltage times for the arc to extinguish, at least if fed by single-phase.  If fed by 3-phase, there will be no zero-voltage times.
« Last Edit: July 26, 2022, 04:34:09 AM by davekni »
David Knierim

Offline Mike

  • High Voltage Enthusiast
  • *
  • Posts: 25
  • Karma: +2/-0
    • View Profile
Re: Gate waveform question
« Reply #8 on: July 26, 2022, 06:08:01 AM »
Quote
However I'd thought you were using 5.1ohm (5R1) gate resistors.
It could be, it's hard to read the resistor codes in the images, it looks like black brown gold, though I wasn't aware that was a valid banding. If it's actually green brown gold it would make a lot more sense.

Offline flyingperson23

  • High Voltage Enthusiast
  • *
  • Posts: 19
  • Karma: +0/-1
    • View Profile
Re: Gate waveform question
« Reply #9 on: July 26, 2022, 03:57:42 PM »
My gate resistors are 5R1. The circuit breaker is just a contactor to discharge the bus capacitors. I'll try lowering the inductance as much as possible. I don't know why the 30v zeners aren't clamping properly, I'll see if I have maybe some 25-30v ones I can test.

Offline Mads Barnkob

  • Administrator
  • High Voltage Expert
  • *****
  • Posts: 1980
  • Karma: +52/-0
  • Denmark
    • View Profile
    • Kaizer Power Electronics
Re: Gate waveform question
« Reply #10 on: July 27, 2022, 02:17:25 PM »
You are building a DRSSTC inverter and not a life saving device. Surgeon precision waveforms are not needed :)

The components are being pushed and their life time in a DRSSTC is already shortened considerable from the rapid and large thermal expansion/contractions.

IGBT gates are rather sturdy and will not break down until 80 VDC+, but limiting gate voltage is also limiting C-E junction current, so its a good idea to keep it under control. More details on all this here: http://kaizerpowerelectronics.dk/tesla-coils/drsstc-design-guide/igbts/

Personally I would not worry or do anything about 10% overshoot at FULL DC BUS voltages! Lower DC BUS voltage testing can give deceiving results in terms of relative spike/overshoot voltages. As its mentioned, the capacitances in the IGBT is fixed and thus will have a greater ratio/influence at lower voltages.
https://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!

High Voltage Forum

Re: Gate waveform question
« Reply #10 on: July 27, 2022, 02:17:25 PM »

 


* Recent Topics and Posts

post Re: SCR precharge
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
August 07, 2022, 07:28:51 PM
post Re: Bipolar CW -- update
[Voltage Multipliers]
abstruse1
August 07, 2022, 07:15:11 PM
post Re: BrOdin coil - High power Big sparks!
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
August 07, 2022, 06:46:44 PM
post Re: SCR precharge
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alexhanyuan
August 07, 2022, 06:11:59 PM
post Re: BrOdin coil - High power Big sparks!
[Dual Resonant Solid State Tesla coils (DRSSTC)]
fh89
August 07, 2022, 08:25:56 AM
post Re: SCR precharge
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
August 07, 2022, 03:46:50 AM
post SCR precharge
[Dual Resonant Solid State Tesla coils (DRSSTC)]
alexhanyuan
August 06, 2022, 10:23:27 PM
post Re: MidiStick V2.0: Next gen tesla coil interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
davekni
August 06, 2022, 09:34:35 PM
post Re: Can someone help, am not getting any plasma :-) much appreciated
[Spark Gap Tesla Coils (SGTC)]
ItsChloeUwU
August 06, 2022, 07:49:05 PM
post Re: Primary Wire Getting Hot, Secondary flashovers, RSG Not Alway Fireing? Help pls.
[Spark Gap Tesla Coils (SGTC)]
ItsChloeUwU
August 06, 2022, 07:42:00 PM
post Re: MidiStick V2.0: Next gen tesla coil interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
AstRii
August 06, 2022, 07:05:35 PM
post Re: MidiStick V2.0: Next gen tesla coil interrupter
[Computers, Microcontrollers, Programmable Logic, Interfaces and Displays]
TMaxElectronics
August 06, 2022, 04:06:48 PM
post Re: CORE FOR GDT AND CT
[Solid State Tesla Coils (SSTC)]
Didik
August 05, 2022, 11:59:58 AM
post Re: CORE FOR GDT AND CT
[Solid State Tesla Coils (SSTC)]
Rafft
August 05, 2022, 09:56:26 AM
post Re: CORE FOR GDT AND CT
[Solid State Tesla Coils (SSTC)]
davekni
August 05, 2022, 06:25:39 AM
post Re: Where To Get "Free" TO-247 IGBTs and MOSFETs
[Electronic Circuits]
Mads Barnkob
August 04, 2022, 08:50:24 PM
post Re: CORE FOR GDT AND CT
[Solid State Tesla Coils (SSTC)]
Didik
August 04, 2022, 08:08:09 AM
post Re: Where To Get "Free" TO-247 IGBTs and MOSFETs
[Electronic Circuits]
Max
August 02, 2022, 07:36:07 PM
post Re: a substitute for FDD8424H
[Dual Resonant Solid State Tesla coils (DRSSTC)]
hammertone
August 02, 2022, 02:34:46 PM
post Re: a substitute for FDD8424H
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hydron
August 02, 2022, 11:59:53 AM
post Where to find a "small" focal spot x-ray tube
[X-ray]
Davide
August 01, 2022, 10:21:53 PM
post Re: a substitute for FDD8424H
[Dual Resonant Solid State Tesla coils (DRSSTC)]
hammertone
August 01, 2022, 06:07:03 PM
post Re: Where To Get "Free" TO-247 IGBTs and MOSFETs
[Electronic Circuits]
ZakW
July 31, 2022, 10:27:33 PM
post Where To Get "Free" TO-247 IGBTs and MOSFETs
[Electronic Circuits]
Mads Barnkob
July 31, 2022, 08:57:46 PM
post Re: Help for people buying the "12-48 Volt 1800/2500 Watt ZVS induction Heater"
[Electronic Circuits]
petespaco
July 31, 2022, 06:36:38 PM
post Re: Primary Wire Getting Hot, Secondary flashovers, RSG Not Alway Fireing? Help pls.
[Spark Gap Tesla Coils (SGTC)]
ItsChloeUwU
July 31, 2022, 04:56:53 PM
post Re: Successful flyback/xformer driver above 3kw
[General Chat]
davekni
July 31, 2022, 12:14:19 AM
post Re: Primary Wire Getting Hot, Secondary flashovers, RSG Not Alway Fireing? Help pls.
[Spark Gap Tesla Coils (SGTC)]
ItsChloeUwU
July 30, 2022, 08:46:44 PM
post Re: Primary Wire Getting Hot, Secondary flashovers, RSG Not Alway Fireing? Help pls.
[Spark Gap Tesla Coils (SGTC)]
Mads Barnkob
July 30, 2022, 08:34:09 PM
post Re: Primary Wire Getting Hot, Secondary flashovers, RSG Not Alway Fireing? Help pls.
[Spark Gap Tesla Coils (SGTC)]
ItsChloeUwU
July 30, 2022, 01:06:49 PM
post Re: Primary Wire Getting Hot, Secondary flashovers, RSG Not Alway Fireing? Help pls.
[Spark Gap Tesla Coils (SGTC)]
Mads Barnkob
July 30, 2022, 10:20:31 AM
post Re: Successful flyback/xformer driver above 3kw
[General Chat]
Mads Barnkob
July 30, 2022, 10:17:13 AM
post Successful flyback/xformer driver above 3kw
[General Chat]
oneKone
July 30, 2022, 04:55:51 AM
post Primary Wire Getting Hot, Secondary flashovers, RSG Not Alway Fireing? Help pls.
[Spark Gap Tesla Coils (SGTC)]
ItsChloeUwU
July 30, 2022, 01:34:27 AM
post Re: Reverse Engineering a Design for a Transmitter - Real Deal
[General Chat]
Distilled29
July 29, 2022, 09:58:33 PM
post Re: a substitute for FDD8424H
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Hydron
July 29, 2022, 03:18:59 PM
post Lightnovo Raman Spectrometer Demonstration At Roskilde Festival 2022
[Science, Research and News In Other Fields Than Electronics]
Mads Barnkob
July 29, 2022, 02:52:32 PM
post Re: a substitute for FDD8424H
[Dual Resonant Solid State Tesla coils (DRSSTC)]
oneKone
July 29, 2022, 11:53:16 AM
post a substitute for FDD8424H
[Dual Resonant Solid State Tesla coils (DRSSTC)]
hammertone
July 29, 2022, 11:03:59 AM
post AC v. Pulsed DC for transformers
[General Chat]
abstruse1
July 29, 2022, 05:50:32 AM
post Re: Solder v. Wago junctions
[General Chat]
abstruse1
July 29, 2022, 05:29:43 AM
post Re: Full wave CW Multiplier possible punch through
[Voltage Multipliers]
FonziDaytona
July 29, 2022, 12:51:08 AM
post Re: DRSSTC from Aliexpress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
July 28, 2022, 08:57:59 PM
post Re: A big-ish diy xformer
[Transformer (Ferrite Core)]
FonziDaytona
July 28, 2022, 02:19:26 PM
post Re: Help with TC schematic
[Solid State Tesla Coils (SSTC)]
MoonMatthew
July 28, 2022, 01:52:46 PM
post Re: Help with TC schematic
[Solid State Tesla Coils (SSTC)]
AstRii
July 28, 2022, 12:40:29 PM
post Re: Help with TC schematic
[Solid State Tesla Coils (SSTC)]
MoonMatthew
July 28, 2022, 11:12:50 AM
post Re: Just a quick question on NST insulation...
[Spark Gap Tesla Coils (SGTC)]
AstRii
July 28, 2022, 06:06:58 AM
post Re: OKY CHAT... EXPLAIN ME THIS SORCERY PLS... Xshion Coil on AliexPress?!
[Dual Resonant Solid State Tesla coils (DRSSTC)]
AstRii
July 28, 2022, 05:59:17 AM
post Re: Help with TC schematic
[Solid State Tesla Coils (SSTC)]
AstRii
July 28, 2022, 05:42:54 AM
post Re: Full wave CW Multiplier possible punch through
[Voltage Multipliers]
davekni
July 28, 2022, 04:06:37 AM
post Re: Help with TC schematic
[Solid State Tesla Coils (SSTC)]
davekni
July 28, 2022, 03:57:19 AM
post Re: gdt is giving a perfect signal and good current but the mosfet are not swithing
[Solid State Tesla Coils (SSTC)]
davekni
July 28, 2022, 03:46:15 AM
post Just a quick question on NST insulation...
[Spark Gap Tesla Coils (SGTC)]
ItsChloeUwU
July 28, 2022, 03:35:48 AM
post DRSSTC from Aliexpress
[Dual Resonant Solid State Tesla coils (DRSSTC)]
ItsChloeUwU
July 28, 2022, 03:27:40 AM
post Re: Looking for a good schematic to follow for my first audio sstc coil :3
[Solid State Tesla Coils (SSTC)]
ItsChloeUwU
July 28, 2022, 03:19:17 AM
post Re: A big-ish diy xformer
[Transformer (Ferrite Core)]
oneKone
July 28, 2022, 03:04:48 AM
post Re: A big-ish diy xformer
[Transformer (Ferrite Core)]
oneKone
July 28, 2022, 03:00:59 AM
post Re: Full wave CW Multiplier possible punch through
[Voltage Multipliers]
FonziDaytona
July 28, 2022, 01:40:37 AM
post Re: A big-ish diy xformer
[Transformer (Ferrite Core)]
FonziDaytona
July 28, 2022, 01:18:31 AM
post gdt is giving a perfect signal and good current but the mosfet are not swithing
[Solid State Tesla Coils (SSTC)]
alex
July 27, 2022, 11:21:13 PM
post Help with TC schematic
[Solid State Tesla Coils (SSTC)]
MoonMatthew
July 27, 2022, 07:01:22 PM
post Re: Secondary former material
[Spark Gap Tesla Coils (SGTC)]
55#sofcopper
July 27, 2022, 06:15:44 PM
post Re: Gate waveform question
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
July 27, 2022, 02:17:25 PM
post Re: Looking for a good schematic to follow for my first audio sstc coil :3
[Solid State Tesla Coils (SSTC)]
Mads Barnkob
July 27, 2022, 02:10:20 PM
post Re: Secondary former material
[Spark Gap Tesla Coils (SGTC)]
Mads Barnkob
July 27, 2022, 02:07:24 PM
post Re: A big-ish diy xformer
[Transformer (Ferrite Core)]
Mads Barnkob
July 27, 2022, 02:01:29 PM
post Secondary former material
[Spark Gap Tesla Coils (SGTC)]
55#sofcopper
July 27, 2022, 08:06:36 AM
post Re: Looking for a good schematic to follow for my first audio sstc coil :3
[Solid State Tesla Coils (SSTC)]
AstRii
July 27, 2022, 05:40:14 AM
post Smoke detector carrying plutonium
[General Chat]
farleymartinez
July 27, 2022, 04:37:44 AM
post Re: Looking for a good schematic to follow for my first audio sstc coil :3
[Solid State Tesla Coils (SSTC)]
ItsChloeUwU
July 26, 2022, 09:45:49 PM
post Re: Looking for a good schematic to follow for my first audio sstc coil :3
[Solid State Tesla Coils (SSTC)]
ItsChloeUwU
July 26, 2022, 09:45:37 PM
post Re: Looking for a good schematic to follow for my first audio sstc coil :3
[Solid State Tesla Coils (SSTC)]
ItsChloeUwU
July 26, 2022, 09:44:28 PM
post Re: Looking for a good schematic to follow for my first audio sstc coil :3
[Solid State Tesla Coils (SSTC)]
ZakW
July 26, 2022, 06:00:18 PM
post Re: Looking for a good schematic to follow for my first audio sstc coil :3
[Solid State Tesla Coils (SSTC)]
AstRii
July 26, 2022, 04:22:27 PM
post Re: Looking for a good schematic to follow for my first audio sstc coil :3
[Solid State Tesla Coils (SSTC)]
ItsChloeUwU
July 26, 2022, 04:15:51 PM
post Re: Looking for a good schematic to follow for my first audio sstc coil :3
[Solid State Tesla Coils (SSTC)]
ItsChloeUwU
July 26, 2022, 04:11:27 PM
post Re: Gate waveform question
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
July 26, 2022, 03:57:42 PM
post Re: Looking for a good schematic to follow for my first audio sstc coil :3
[Solid State Tesla Coils (SSTC)]
AstRii
July 26, 2022, 08:59:32 AM
post Re: Gate waveform question
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mike
July 26, 2022, 06:08:01 AM
post Re: A big-ish diy xformer
[Transformer (Ferrite Core)]
oneKone
July 26, 2022, 05:51:33 AM
post Re: A big-ish diy xformer
[Transformer (Ferrite Core)]
davekni
July 26, 2022, 04:41:00 AM
post Re: Gate waveform question
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
July 26, 2022, 04:24:36 AM
post A big-ish diy xformer
[Transformer (Ferrite Core)]
oneKone
July 26, 2022, 04:10:58 AM
post Re: 60 hz hum in KLH receiver
[Electronic Circuits]
davekni
July 26, 2022, 03:48:23 AM
post Re: Gate waveform question
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mike
July 26, 2022, 03:10:06 AM
post Re: Gate waveform question
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
July 26, 2022, 01:46:12 AM
post Re: 60 hz hum in KLH receiver
[Electronic Circuits]
petespaco
July 26, 2022, 12:16:12 AM
post Re: 60 hz hum in KLH receiver
[Electronic Circuits]
Twospoons
July 25, 2022, 11:55:33 PM
post 60 hz hum in KLH receiver
[Electronic Circuits]
MRMILSTAR
July 25, 2022, 10:20:45 PM
post Re: Gate waveform question
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
July 25, 2022, 05:18:07 PM
post Looking for a good schematic to follow for my first audio sstc coil :3
[Solid State Tesla Coils (SSTC)]
ItsChloeUwU
July 25, 2022, 03:23:13 PM
post Total Pro Tp40 Servis Manuel Gerekli
[Spark Gap Tesla Coils (SGTC)]
Cem888
July 24, 2022, 10:16:27 PM
post HBK-2216 power supply
[Electronic Circuits]
costas_p
July 24, 2022, 12:15:54 PM
post Re: Racing arcs on secondary
[Spark Gap Tesla Coils (SGTC)]
MRMILSTAR
July 24, 2022, 05:06:32 AM
post Re: Gate waveform question
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
July 24, 2022, 04:15:16 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