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    Why are 1.5mm thick PCB not common?

    Hi I had someone request for a 1.5mm PCB. This is the first that I have even heard of it, but after some searching found that most in Europe seem to be prototyping with 1.5mm thickeess. Its just 0.1mm from the common 1.6mm FR-4 type boards. I am not sure if its just that they ignore the 0.1mm...
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    MOC30xx type isolators for 380Vac application (TRIAC firing)

    Hi All, Does anyone know if there are any MOC30xx or similar optocouplers available for 380Vac application. I am current using MOC3022 which has a output repetitive of only 400V which only allows me to fire my TRIAC at about 48 deg. sin angle. I want to be able to go 90 deg. which would be...
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    CT Design not clean on the signal end

    Hi All, I am trying to build an AC current monitoring device which would allow me to sample AC incoming current using a MURATA 1:100 current transformer. When I use the scope to see the signal I can make out the waveform of the lamp I am using as load but its not clean it has alot of noise...
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    Pulse transformer to drive scr circuit

    Hi I am trying to drive an SCR using a pulse transformer with the following circuit I got an MCU to swtich the MOSFETs are about 1 second interval repeated the total current to the transformer is about 200mA but there is no voltage on the output side. I am using a 1:1 78601/2C pulse...
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    How does a automatic self-test work on AFCI?

    Just wondering how an automatic self-test can perform and work on AFCI units. I can understand the push button test but for the unit to on its own create an arcing simulation or am I missing something here on the self-test part?
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    Ferrite Core d3,4/l3,2 -> What is this?

    Ferrite Core d3,4/l3,2 -> What is this? Hi I am trying to find the matching ferrite core all I have is this part number Ferrite core d3,4/l3,2 I am not able to locate it anywhere - - - Updated - - - OK, I think it should the following. Dia - 3.4 mm Length - 3.2 mm
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    2 x Current transformer what is the reason?

    Hi I recently saw an AFCI with 2 current transformer built into it. One of them had the Live wire going thru it the other smaller than the first had the the Live and Neutral. I am not sure why they have to sample the same current 2 times and what different would placing the L and N into the...
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    [SOLVED] Back EMF from relay resets MCU

    Hi I have a problem with back EMF from a relay. But when its not connected to the 220V devices the MCU will not freeze. I have tried using snubber and diode combo to try to cut it down but there is still the problem persist. I am thinking if I were to sample the current from the 220V line and...
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    DC/DC Boost converter with 95% eff.? GaN MOSFETs

    Hi I am trying to build a boost converter with 95% eff. I have looked around for some solution but most of the them seem to be around 90% - 92% eff. I am thinking of using GaN MOSFETs to try to push the eff. up, I have not used these before not sure if they might help much. Other things like...
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    [SOLVED] Transformer in Series wiring

    Hi I am have tried to put 2 6kV transformer in series to get 12kVrms but seems like I am only getting about 8kV, not sure why here is the circuit diagram. Doesnt look like there is anything wrong with it. I checked each transformer and they both give 6kV respectively.
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    Start up time for transformer how to overcome it?

    Hi I have this small problem. I am using a 20kV transformer and not sure why this seems to require a start-up it might be to energize the coil. The total time it takes is about 5ms. Which is too long for my application. Is there a way to reduce this start-sup time or at best remove it...
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    ADC sampling of voltage >500V

    Hi I am thinking of sampling a 500Vdc line but I like to be as accurate as possible. The device I am using (16-bit adc) to sample it has a range of 20V (-10V to 10V). This is selectiable to even 2V. I know that I have to use a voltage divider to bring down the voltage to the level that will...
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    Transformer not giving 10kV

    Hi I have a simple circuit where I just need to give a 7kV to a surge protector to see if it works. However I dont seem to be able to ignite it. The transformer is 380VAC on the pri and 10kV on the secondary I am triggering the SCR at 30 deg. The trigger on scope it perfectly at 30 deg. but...
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    Small 3 phase motor controller 2.5A

    Can anyone recommend a 3 phase driver IC that might be able to handle breaking and microstepping on a 4 pole 3 phase motor that draws MAX. 2.5A, or if you might have some recommendation for a ready made module that is 40 x 50 mm in size height is not a problem it can be stacked.
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    Trying to switch on my SCR

    Having a bit of a problem trying to switch on my SCR, I have hooked it to a 380VAC source and used the following schematic https://www.tablix.org/~avian/blog/images2/2011/03/scr_trigger_using_an_optoisolator-t.jpg It works fine on a lower votlage but when its going into a 380VAC it turns on...
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    MOSFET to switch AC load that is a transformer

    I have the following MOSFET circuit and its working without the load connected https://3.bp.blogspot.com/-GiA1j0kY28o/Ty1_jkqLadI/AAAAAAAAAEI/xFyTbD4RnhI/s320/ac+switch.png Once I connect the Neutral which goes to a 220V to 380V transformer and fire the mosfet for just 1ms it kills the...
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    How to measure voltage of above 10kV using an MCU

    I am trying to find a way to safely sample a high voltage output which will travel from about 1kV to 20kV (ramp). I think using a resistor divider should do the job. I have been successful at 1 kV - 2 kV range. I am just wondering if just by using a high impedance resistor will do the trick...
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    Testing surge protector by giving it high voltage when 380VAC is present

    Hi I am trying to test my surge protector. I have a HV pulse generator which will give me a peak voltage of 15kV connected parallel to a 380VAC and inbetween is the TDK surge protector. There is 3kohm and 3.3mH in series. When the 380VAC is absent (off) the pulse generator works nicely...
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    Can I monitor a 1.4kV on an MCU via voltage div.? Will this break the MCU?

    Hi I like to see if I can monitor the strike voltage on a lamp by a ballast, the strike voltage is about 1400V, using R1 to be 1M ohms and R1 to be 2.2k ohms on the divider I should see about 3.0V on the MCU's ADC pin, this looks workable but the most I have tried and seen working was 300V in...
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    weigh checker using load cell?

    I am trying to see if I can build a kind of weight checker system using load cell on a conveyor, the sensitivity should be measuring up to 1g. I am not sure how some products are able to achieve this. Anyone has any insight into this?

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