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Type: Posts; User: FvM

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  1. [SOLVED]Closed: Re: Current source for high current LED driver- 24Vdc/max:16A

    Bulk capacitors are fine to source pulse currents, but the OP is planning 100 ms pulse duration if I understand right. You'll need huge (100 mF range) capacitors for it. Providing a 15 or 20 A rated...
  2. Closed: Re: Audio amplifier on PCB error. Ports of opAmp shorted.Can't find the reason why?

    Which circuit are you talking about now? Post #1 or post #4?

    - - - Updated - - -


    Doesn't make sense. How do you measure?
  3. [SOLVED]Closed: Re: Current source for high current LED driver- 24Vdc/max:16A

    The circuit in post #1 is no correct constant current source. The gate voltage, at least the DC value, should be fed to the current controller.
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    Closed: Re: LTspice: Modelling a negative resistor

    This works for a constant or only time dependent resistor. If the resistance is also a function of another node voltage or branch current, it has to be implemented by a behavioral expression, most...
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    Closed: Re: LTspice: Modelling a negative resistor

    Not specifically, review help for "B. Arbitrary Behavioral Voltage or Current Sources"
  6. Closed: Re: Any way to make a rounded rectangle non-plated hole in Altium?

    Polygon can include arcs. I guess, you just haven't found how to draw it.

    I don't specifically know with Altium, but all quality PCB tools that I know can include PCB contours in a footprint.
  7. [SOLVED]Closed: Re: Current source for high current LED driver- 24Vdc/max:16A

    Ground short is a problem to consider if you can't guarantee the quality of external wiring. Don't know how it is in your design?

    If the driver is placed next to the LEDs, e.g. on a common PCB, I...
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    Closed: Re: Differential probe build

    O.K., if you can live with AD8130 common range, this is surely an option. I have used it in a number of design, particularly high MHz current sense. +/- 10V is only achieved with high supply voltage,...
  9. Closed: Re: Any way to make a rounded rectangle non-plated hole in Altium?

    Think of the non plated hole as a board cutout. There are no limitations for it, except for available milling tools. If you want a radius below e.g. 0.5 mm, clear with the PCB house first.
  10. [SOLVED]Closed: Re: Current source for high current LED driver- 24Vdc/max:16A

    Why particularly? I don't recognize any advantage if you are free connect the LED string as you want.
  11. Closed: Re: Car battery STARTER voltage help (not charger) using variety of methods (possibly

    The term booster seems to refer to using the existing battery, not an external supply. At least no external supply is mentioned in your original post, or does "possibly AC" refer to it?. Without...
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    Closed: Re: LTspice: Modelling a negative resistor

    You mean modelling a voltage controlled negative resistor in the simulator in contrast to designing a real circuit that exposes a negative resistance?

    It can be most easily done with a behavioral...
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    Closed: Re: Differential probe build

    Differential probe is a rather general topic. Beside bandwidth, you want to specify input impedance, common mode range and common rejection ratio before you start any actual design work.

    The...
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    Closed: Re: Every few Hours clock running fast rtc1307

    What does running fast for 1 sec actually mean? How much is the time advancing?
  15. Closed: Re: Car battery STARTER voltage help (not charger) using variety of methods (possibly

    Seriously I don't get of which kind of boosting you are talking.

    Is it about bosting the voltage for the starter or the ignition system? Boosting the starter voltage would require large super...
  16. Closed: Re: measuring slow oscillations with magnetic methods

    Acceleration sensors are the usual tool to measure mechanical oscillations. For the intended low frequency range cheap MEMS accelerometers may be used, they have up to kHz bandwidth.
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    Closed: Re: High Frequency using 8051

    I skip the "perfect" square wave discussion. To get a square wave at all, you need a free-wheeling diode.
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    Closed: Re: Capacitor Burning issue due to unusual reasons

    Both ground nets are apparently connected by a SMD jumper next to the 10µF input capacitor.

    The ground net isn't exposed at the solenoid connector, only at the input connector.
  19. [SOLVED]Closed: Re: does copper tape need grounding when sheilding plastic enclosure

    Yes, without grounding mains hum and similar interferences won't be blocked.
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    Closed: Re: High Frequency using 8051

    Yes, more or less.
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    Closed: Re: hbridge control from mcu

    I was referring to your provided info saying IRF540 and 20V supply.
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    Closed: Re: Capacitor Burning issue due to unusual reasons

    To achieve what, particularly? 2803 diodes are just fine for regular solenoid load, no reason to add anything. If you fear shorted solenoids however, a series resistor would either have no...
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    Closed: Re: Load pull values as frequency increases

    The optimum load impedance curve represents the output impedance of your power stage and depends on it's topology and component parameters, also on the transmission line length between PA and your...
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    Closed: Re: Capacitor Burning issue due to unusual reasons

    You didn't yet answer the question if the burned capacitor was observed in the single side post #1 or double side post #15 PCB. You say "We will plan for 2 Layer", sounds like the #15 PCB exist only...
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    Closed: Re: High Frequency using 8051

    The gate driver is connected wrongly. It's a complementary emitter follower, should have NPN on top and PNP on the bottom. Both emitters tied to the gate. No base resistors required, instead an...
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