Type: Posts; User: carpenter

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  1. Replies

    Closed: Re: Old HP design schematics habits?

    There is a position on the board for the parts, but they are not physically there in my piece, but there was no amplifier U13. I don't know what the fate of my piece was, but somebody was already...
  2. Replies

    Closed: Old HP design schematics habits?

    Hello ,
    I repair or more precise restoring old HP Electronics Load , I have service manual with list of parts and full schematics.
    And have problem.
    See on picture, for example R173+R173+D34 they...
  3. Replies

    Closed: Re: Precise current sesnse amplifier.

    You have to look at it this way.
    For example 10mOm shunt and between - of shunt and GND is 20cm Cu wive 2,5mm2
    For 20C we have

    Rshunt 10,00 mOhm
    Rwire 1,53 mOhm

    for 40C we have
  4. Replies

    Closed: Re: Precise current sesnse amplifier.

    Because he wants to measure accurately,
    even on a low side can be behind a shunt any pcb, wire, connector and that all have any resistence and therefore, a differential amplifier should also be...
  5. Replies

    Closed: SOT-227B max raal power disipation?

    I want to use a transistor IXFN132N50P3 in electronic load,, for testing high current PS.

    IXFN132N50P3 have max short power disipation 1500W and Thermal Impedance 0,1 C/W.

    1. I have old CPU...
  6. Replies

    Closed: Narrowband filter on 50Hz?

    On line, we have 230V 50Hz and sometimes control frequency 180Hz, the controll signal is 100 weaker.
    I need to evaluate the presence of the control frequency. I use MCU and Goertzel algorithm, its...
  7. Closed: Re: Transformerless / transformer Power Supply Design?

    For example 0,35VA HAHN page 22 noload power loss type 1,2W for 0,5VA noload power loss type 1,5W , if we neet 6V 20mA 0,125W => big tragedy :-D

    - - - Updated - - -

    Another power supply...
  8. Closed: Re: Transformerless / transformer Power Supply Design?

    That is a question, maybe yes may be not.
    The key question is the efficiency of a small transformer 0,35 or 0,5VA .
    My guess is, it will be one big tragedy, but I am wrong, there is some real...
  9. Closed: Re: SPI digital isolator adum41521 idle current consuption and replcement

    Unfortunately, in the datasheet you would seek this information in vain.
    In dataseet is in table 5. is information only for 1MHz and 17MHz comunications speed , maybe Figure 9. and 12. but this is...
  10. [SOLVED]Closed: Re: MAX31856 how increase thermocouple ESD protection?

    You're right, but
    - bipolar device - in the thermocouple circuit is not negative voltage
    - parasitic capacotnace - all thermocouple input they are against the earth 10nF capacitor I...
  11. [SOLVED]Closed: Re: MAX31856 how increase thermocouple ESD protection?

    I concact Maxim Integrated and her is information from technical support.

    DRDY - is push-pull. And so, unfortunately, their direct connection is not possible.
    Using external ESD diode on T+ T- is...
  12. [SOLVED]Closed: Re: MAX31856 how increase thermocouple ESD protection?

    If I got it right, all intup and T+ T- too are provided internal protection diode for max continuaous current 20mA.
    Tthese diodes allow on T+ T- vlong time voltage +-45V and short time ESD 2000V ....
  13. Replies

    Closed: Re: Mains voltage data logger

    why do not you measure on the secondary side of the transformer when you already have it?
  14. [SOLVED]Closed: MAX31856 how increase thermocouple ESD protection?

    MAX31856 is precise 19bit Thermocouple to Digital Converter with Linearization and have on T+ T- input protection on +-45V. The range can be increased by resistors, but it brings a number of...
  15. Replies

    Closed: Re: Low cost amplifier for 12bit ADC SAR?

    Accuracy and precision

  16. Replies

    Closed: Re: Power supply questions

    On anode the ideal diode will be 0V between anode and Ground, becouse diode is in councluding direction.
    Real diode have any small leakage current for example 2uA and it will depend on the...
  17. Replies

    Closed: Grounding on high current PCB?

    Imagine a simple PCB on high side is connecotr for 100A, in center switching MOSFET Rds On 1mOhm, and on low side PCB again connector for 100A to high current ground in power supply.
    On board is too...
  18. Closed: Re: Output inverter bridge for welding TIG machine?

    It will be, on the other hand, switching current is 150A, Qoss 208nC and no-load voltage may be 50V. For mimimising switching lost we need mimimise switching time
    if we want to open transistor on...
  19. Replies

    Closed: Re: High side current sense Amplifer

    INA28x have bandwith only 10kHz or low ,
    AD841x for example AD8417 with G=60 is good choice but if is powered GND +5V is mimimum output voltage about 55mV , i,e. for 3mOhm shunt this solution not...
  20. Replies

    Closed: Re: SMD IC identification

    1. PVT312 ralay is in 6pin DIP and size equivalent SMD case, but my IC is in SMD case of size SOT23-6 . Relay on 250V in SOT23-6 is nonsense, because of insulation distances.
    2. Yes I look on SMD...
  21. Replies

    Closed: Re: SMD IC identification

    I will restore my old theme.

    I still looking

    SMD marked as 312S (above the three is a dot)
    function is simple switched 5V 500mA max from input pin 5 to output pin 2 , switchung drive MCU over...
  22. Replies

    Closed: SMD IC identification

    i have on PCB any SMD IC with this code

    1. size any as MSO8

    2.size any as SOT23-5

    3 size any as DPY23-6
  23. Closed: Re: 1.5Amps FET, MOSFET to work with 5v device.

    AOD514 , IRLR7807Z, IRLU7807Z ,FDT457N , IRLL3303, IRLML2030TRPbF,IRLML6244TRPbF and many other
  24. Closed: Re: Voltage rating for MOSFET in full bridge?

    400% on full bridge?
    How and where?
  25. Closed: Re: Electronic Load - conception and transistor choice.

    Ok here is the first draft.,

    AS Load is used Mosfet IXFN100N50Q3 RdsOn 49mOhm and in China price under 10$ + 10m Ohm Shunt 10W (in real 50W from china)
    Current on MOSFET is measured over U1B...
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