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  1. [SOLVED]Closed: Re: Center tapped transformer (forward converter)

    Do you have any load on the +12V output?
    With no load, overshoots and ringings can be rectified by the diode and increase the output voltage.
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    Closed: Re: N7j3a marking transistor

    It is a normal bipolar PNP transistor. BC847 will not work since it is NPN. Try BC857 or BC807.
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    Closed: Re: HP 54520A Blown Fuse Problem

    Measure the voltages over C22 and C23 before the problem happens. The center voltage should be stable and half of +V.
    If the leakage is too high, the center voltage can slowly drift away and cause...
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    Closed: Re: N7j3a marking transistor

    It isn't a MOSFET because the gate-source voltage would be 24V.
    It seems to be a bipolar PNP transistor, maybe a Darlington (depends on how much current the relay needs).
    2N2222 is NPN, so it will...
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    Closed: Re: Error in Parity bits of Hamming Code

    It is hard to understand what you want.
    A Hamming Code makes no difference between data bits and parity bits regarding error correction. It will correct any single bit error and detect any double...
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    Closed: Re: HP 54520A Blown Fuse Problem

    The output voltages and the crowbar circuit should be checked first.
    There are 8 different voltages involved in the crowbar triggering. 7 of them can be adjusted.
    The +15.5V output can't be...
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    Closed: Re: overvoltage protection

    My understanding is that the OP wants an additional protection close to the MCU.

    1) Normally 5V in and 5V out for the low dropout regulator. If the 5V from the external power supply has an...
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    Closed: Re: N7j3a marking transistor

    The "N" looks different, so maybe the marking begins with "7J".
    Only "7J" is a FMMT38C, a 60V NPN darlington transistor, but I find nothing where also "3A" is included in the marking.
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    Closed: Re: overvoltage protection

    The ferrite bead will do nothing. The others will not protect 5V digital circuits from a power supply overvoltage. They don't have a sharp enough "knee". The voltage will be well above 5V before they...
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    Closed: Re: What might be wrong with this old piano?

    Do both "pianos" have the same polarity for the power connector?
    How old are your kids?
    Both instruments are toys, and can not be used for serious piano learning.
    If any of the kids is interested...
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    [SOLVED]Closed: Re: testbench display for CRC code

    There are several things that can go wrong with a CRC implementation.
    The initial value is not as simple as it sounds.
    The direct serial implementation from the mathematical equations is normally...
  12. Closed: Re: A Powerful 30A DC Motor Driver using Power Mosfets [PWM Controlled, Half Bridge]

    I see nothing wrong with the design, but there is some missing information.

    The duty cycle can not go to 100% because the output must repeatedly go low to keep the bootstrap capacitor C3 charged....
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    Closed: Re: uln2003 base resistor

    10k is a good value.

    How to calculate the approximate value that gives 5V at the ULN2803 input:
    Input current at 5V = (5V - 1.4V) / 2700 Ohms = 1.3 mA (ignoring the 100 uA in the internal...
  14. Closed: Re: MOSFET linear and saturation region operation

    I have designed power outputs with MOSFET's where the short circuit protection was implemented using the Ids/Vgs diagram in the datasheet.
    By not switching on the MOSFET to reach the minimum Rds, it...
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    Closed: Re: Advanced VHDL book recommendation

    Are you decoding "next_state" in the clocked process to decide what should be assigned to the outputs?
    Then I understand how you can create registered outputs without the delay you criticize in...
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    Closed: Re: Advanced VHDL book recommendation

    The old thread mentions the following article (in a post by dpaul), but has no direct link to it:

    http://adiuvoengineering.com/microzed-chronicles-finite-state-machines-tips/

    The article...
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    Closed: Re: Advanced VHDL book recommendation

    All designers will probably not agree with me, but avoid books (or at least the chapter) that discuss Moore and Mealy state machines and tell you to write them with two processes, one clocked and one...
  18. Closed: Re: Power Supply for M95 GSM module to be compatible with ATEX limitations.

    I was involved in a power supply design for a GSM module.
    It was not for ATEX, so maybe you have no use for this information.
    When we calculated the capacitance needed to keep the supply voltage...
  19. Closed: Re: Make a led shut down immediately after power off

    Add a second rectifier (full or half wave) and a much smaller capacitor (or no capacitor) for driving the LED.
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    Closed: Re: Multiple relay with controllers

    Please read the data sheet. The signals to be switched must be between VCC and VEE. VEE can be lower than GND.
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    Closed: Re: Multiple relay with controllers

    VEE is the negative limit for the switches and it can be connected to a negative voltage if signals going below GND are switched.
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    Closed: Re: obtaining thermal rise in diode

    @TT = +75C is the terminal temperature. It is in the "maximum" section, so the diode is rated for max 5A when the terminal temperature is +75C.
    Vf @5A according to table 2 is about 1.05V @25C. Power...
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    Closed: Re: Asynchronous reset mechanism

    If the problem is shown in the timing diagram in post #1, the only explanation i see is that reset goes to '0' just before the positive clock edge. What clock was used to do the recording?
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    Closed: Re: Asynchronous reset mechanism

    The comment doesn't make sense for the code you show in post #1. I think it's about how write_en is generated,
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    Closed: Re: Asynchronous reset mechanism

    I think you show us the wrong part of the source code. Please show the code that generates write_en.
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