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    [SOLVED]Closed: Re: IGBT Overshoot and Weird Slope

    I've learned that I need differential probes and probes can be calibrated (except way too cheap probes)
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    [SOLVED]Closed: Re: IGBT Overshoot and Weird Slope

    Thanks , and others for help.

    Found the problem. I'm not commutating, just switching the DC positive ON and OFF. I mean;
    when gate signal high Load = Vdc
    when gate signal low Load = Nothing,...
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    [SOLVED]Closed: Re: IGBT Overshoot and Weird Slope

    I've removed the blue channel, measuring the yellow only. Result is still the same. Still there is a big overshoot.
    Soon I'm going to add a 4700uF 63V capacitor to output rail and test it again.
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    [SOLVED]Closed: Re: IGBT Overshoot and Weird Slope

    I used metal screws so there is electrical conduction. I tested short circuits with middle pin and yes they are electrically connected. I'm not sure if it is the problem. I think I should get a...
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    [SOLVED]Closed: Re: IGBT Overshoot and Weird Slope

    Probe connector is a simple BNC connector. There is no screw. I borrowed probes from a friend and yes they had a screw to calibrate. I calibrated the proble with test signal on oscilloscope. Nice...
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    [SOLVED]Closed: Re: IGBT Overshoot and Weird Slope

    I have been suspecting why there is a little screwdriver in probe packs. Now it's clear =) I'm heading to my workshop. Thanks a lot.

    Update : There is screwdriver but no screw =( Rest of the probe...
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    [SOLVED]Closed: Re: IGBT Overshoot and Weird Slope

    Rheostat is a simple one, 100ohm total, 250Watt. Snubber is not an option at this point. If those overshoots are not a measurement error, I'll try varistor to oppress/suppress (I couldn't decide...
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    [SOLVED]Closed: Re: IGBT Overshoot and Weird Slope

    Yes they are different grounds, It is just ment to observe overall. Trigger is on CH1 and it's on the load which I want to observe best. Disconnecting blue signal doesn't effect yellow. Still same....
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    [SOLVED]Closed: Re: IGBT Overshoot and Weird Slope

    15V supply enclosures are metal and well earthed. I have to use long cables for first prototype. Do you advice me to use twisted pair cables ? Shielded cables ? Ferrite Choker ?


    155529
    ...
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    [SOLVED]Closed: Re: IGBT Overshoot and Weird Slope

    Thanks for reply mate. Going down the list one-by-one. Sorry if sometimes I look rude, it is unintentional and caused by my lack of english skills.


    It is not an DC-AC inverter, it is an AC-AC...
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    [SOLVED]Closed: IGBT Overshoot and Weird Slope

    Hello,

    I'm trying to build a 3phase-3phase direct converter (Explains my schematics). I'm testing IGBT stage with DC source. Circuit is now just triggering IGBT named SAAF.
    Cutting to the chase,...
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    Closed: Re: Serious IGBT overshoot

    That's basically putting a capacitor at source.

    Do you mean there will be an energy stored in PCB because of an stray inductance and bypass it via that capacitor ? What if the input is AC not DC...
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    Closed: Re: Serious IGBT overshoot

    I've been searching for decoupling caps for IGBT like 1 hour a day like 2-3 days. I checked many tutorials, datasheets and application notes. I haven't seen any decoupling capacitors.

    What is the...
  14. Closed: Re: [moved] Calculate the Input/Output Capacitor Value on DCDC converter

    Minimum capacitance formulas for DCDC

    C= (Vout(peak) x DutyCycle% x Switching Period) / (Vripple x Rload)

    or

    C= (Duty Cycle x Imax ) / (Vripple x switching frequency)

    The voltage rating...
  15. Closed: Re: Choosing common mode voltage for inamp (ad623)

    Vcm is for both inputs. It pushes the signal from both sides.

    Speaking regardless of the input/output demans of picture I shared; Is this what I should understood ?

    We have an input signal...
  16. Closed: Re: Choosing common mode voltage for inamp (ad623)

    Thanks FvM.
    My last problem still remains because my MCU has no ADC reference.

    And I'm about to follow Klauss's advice on current measuring. Seems like LEM fluxgate transducers are a bit...
  17. Closed: Choosing common mode voltage for inamp (ad623)

    Hello there,

    I want to measure line-neutral voltage with single supply AD623.

    Grid Line-Neutral voltage 220Vrms
    Input signal for inamp swings between -1V and 1V (Zero crossing at 0V).
    I want...
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    Closed: Re: Bi Directional Switch (Does it shorts ?)

    152836
    I got this transformer and hoping to supply demand.
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    Closed: Re: Bi Directional Switch (Does it shorts ?)

    Thanks for answers. That's a big relief for me because I already ordered my pcb and it takes 1 month to receive.



    152821

    Goal is to synthesizing an AC output at desired V/f, directly from...
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    Closed: Re: Bi Directional Switch (Does it shorts ?)

    152817

    I guess I couldn't express myself because of my poor english skill.

    Vdc sourcing the optocouplers is an isolated (some calls it floating) power supply. But it's - (neutral) is connected...
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    Closed: Bi Directional Switch (Does it shorts ?)

    152816


    The file attached shows a bidirectional switch built with IGBT and optocoupler gate drivers from a paper Click here for article (It's open to public)

    Isolated power supply neutral...
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    Closed: Re: [Help] 1.75V sink voltage reference

    Thanks KlausST,

    Referring to LM741 Datasheet it can swing between +-15V and short circuit current is 25mA. Looks like it can sink. There is no clear sign.
    Can we say it can sink too by looking at...
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    Closed: Re: [Help] 1.75V sink voltage reference

    My load is ~(-1mA). I liked the idea of decreasing amps for Iin. I will increase R3. This part is solved thanks.

    Now my question is "can voltage follower opamps (vfo) sink 1.1mA instead sourcing ?"
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    Closed: Re: [Help] 1.75V sink voltage reference

    Seems like there is TLV431 in stock here. Thanks for great advice. I guess my resistance choices are ok (pdf attachment).
    Now question is should I build 3 different voltage references or share 1...
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    Closed: Re: [Help] 1.75V sink voltage reference

    Hi KlausST

    Sadly MPQ means price for one. I can't buy components directly from farnell nor mouser. I need to buy from a middle dealer. As it seems they don't want to import cheap stuff because...
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