Type: Posts; User: carpenter

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  1. Closed: Toroids EMI suppression choce choice of core material ?


    I have 25V DC line which power RF power amplifier on 15MHz current is about 1A.
    And I need inductor to LPF for suppression all EMI from 15MHz PA from the 25V DC source.
    According to...
  2. Replies

    Closed: Re: Built-in SWR bridge and power meter

    I have two questions about the original SWR design of the bridge by Dominique - F1FRV
    1.Selection of load resistance at bridge voltage outputs

    In original simulation is R5 R3 1M with R2...
  3. Replies

    Closed: Re: RF CV to CC Converter?

    author directly states "stage constitutes the phase shift network of the CV to CC"
  4. Replies

    Closed: Re: MOSFET as dimmier 12VDC 1.2 Amps

    Use any as IRFR3711
    -NMOSFET available in a wider range
    - have low Rdson => lower conductivity losses 6.5mOhm
    - if you want to control the transistor directly from MCU, you have to use logic...
  5. Replies

    Closed: RF CV to CC Converter?

    Yesterday I read a description of some RF construction in which it is on one side
    CV PS freqency over 10MHz and this power variable load (estimated 40 ohm and decreasing to 5 ohm) and between the...
  6. Replies

    Closed: Wire to RF toroidal coils?

    I need to wind up a few toroidal coils on T130 and T50. F=over 10MHz, AC current up to 3A.
    Number of turns 4 to 10.
    For T130 with 7 turn is lenght of wire 300mm.

    I looked at the wires available...
  7. Closed: Re: What is the difference between IRF510 and IRF510N?

    it is a little different.
    IRF510 not a prinary only product of IR, but De facto industry standard manufactured in many campny , today for example IRF510 make Vishay
    and IRF510N was partnumber for...
  8. Replies

    Closed: Re: Decoupling capacitor value

    Follow the manufacturer's recommendations :razz:
    In general for decoupling frequence > 1GHz is good choice use 100pF NPO, smal sice for example 0402. see Picture.
    I recommend to read
  9. Closed: Re: RF Mosfet Class E PA for Dummies or absolute idiots

    I'm not saying it's necessarily, but it can be.
    Cv is the sum of all capacities between D S of switching MOSFET (capacity in series with L1).
    L1 + CV is designed as resonant LC circuit with resonst...
  10. Closed: Re: RF Mosfet Class E PA for Dummies or absolute idiots

    How do you judge class A?
    Whistleblower that anything before G is just hinted and in reality I would expect the first stage of the amplifier with another transistor.
    in any case, just a fool would...
  11. Closed: Choice of capacitors for DC blocking and 3A AC?

    You will deal with choice and sizing DC blocking capacitors for RF power amplifier.

    - DC voltage on RF transistor is under 48V
    - Frequency is over 10MHz
    - AC Current max 3A sinus

    Is a good...
  12. 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...
  13. 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...
  14. 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
  15. 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...
  16. 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...
  17. 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...
  18. 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...
  19. 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...
  20. 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...
  21. [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...
  22. [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...
  23. [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 ....
  24. Replies

    Closed: Re: Mains voltage data logger

    why do not you measure on the secondary side of the transformer when you already have it?
  25. [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...
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