Type: Posts; User: carpenter

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  1. Replies

    Closed: Re: Pressure sensor 0-10bar?

    Honeywell offer absolute pessure sensor 0-150psi HSCMAND150PA4A3
    but is relative expensive and do not forget 150psi is 1034214 Pa and for 14bit sensor is LSB=63Pa
  2. Replies

    Closed: Lowcost Voltage Controled Oscillator?

    Advise a cheap VCO Voltace controled oscilator any as Mini circuit ROP-xxxx , but significantly cheaper for example
    for frequency 900-1000MHz
    for frequency 1500-1700MHz
    for frequency...
  3. Replies

    Closed: Re: ATX power supply switch

    I also dealt quite often with how to operate the On Off button with adjustable timing and other features.
    Yes, this can be done purely analog, delay line as charging or dischrging any capacitor etc....
  4. Replies

    Closed: Re: powerful induction heater advice?

    You need to clarify exactly what you want, what power it has.
    Depending on the power and size of the coils you want to use depends on the required power and especially the frequency you have to...
  5. Replies

    Closed: Re: STM32F3 built-in opertion amplifier

    I was looking at the data of the built-in amplifier.
    can someone explain to me what it is
    VOHSAT High saturation voltage min Vdda-100mV
    VOLSAT Low saturation voltage max 100mV

    Somehow I do...
  6. Closed: Re: Toroids EMI suppression choce choice of core material ?

    You're right. To calculate the inductance I used mini Ring-Core-Calculator
    I assumed he was working with true permeability, big mistake, even sw widespread among radio amateurs counts incorrectly....
  7. 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...
  8. 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...
  9. Replies

    Closed: Re: RF CV to CC Converter?

    author directly states "stage constitutes the phase shift network of the CV to CC"
  10. 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...
  11. 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...
  12. 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...
  13. 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...
  14. 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
  15. 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...
  16. 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...
  17. 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...
  18. 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...
  19. 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...
  20. 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
  21. 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...
  22. 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...
  23. 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...
  24. 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...
  25. 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...
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