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Type: Posts; User: treez

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  1. Closed: Re: Opamp buffer with 400nF output capacitance going unstable?

    Thanks, yes I believe there is a real threat of instability here. Please could you check if the following would be unstable? (schematic attached) I have used “out of loop compensation”, as given on...
  2. Closed: Re: Opamp buffer with 400nF output capacitance going unstable?

    Just to note, I’ve just actually wired in 51.7uF of capacitance in parallel with C2, and its still not gone unstable. (11 pieces of 4u7, 0805, 16v, X7R).

    - - - Updated - - -

    Also, I’ve then...
  3. Closed: Re: Opamp buffer with 400nF output capacitance going unstable?

    Thanks, I will read about “in loop compensation” etc, it sounds good.
    Today I actually addressed our contractor, and tried to talk him out of the circuit of the top post. However, also, I actually...
  4. Closed: Re: Opamp buffer with 400nF output capacitance going unstable?

    Thanks, actually there is some requirement for the opamp to sink current some of the time. 15mA was just an average figure.
    What would you say is the maximum capacitive load allowable for an opamp...
  5. Closed: Opamp buffer with 400nF output capacitance going unstable?

    Hi
    We wish to have this 8V3 Regulator. (attached)
    Do you think the amount of output capacitance will make the MIC6211 opamp go unstable?
    MIC6211 opamp...
  6. Closed: Re: Regulating temperature of mains connected heating element: Skipping mains half cy

    Thanks, yes you are right, controlling temperature by controlling the flow rate appears to be the main method....but it is a poor method....just cheaper....

    What I would add is, that I have lived...
  7. Closed: Do you know the efficiency vs output load for this dcdc module?

    https://www.cui.com/product/resource/pds1-m.pdf

    ..the datasheet doesnt say. It only says "up to 82%"

    Its the PDS1-S12-D15-M one


    *..................................
    Also this one doesnt...
  8. Closed: Re: Regulating temperature of mains connected heating element: Skipping mains half cy

    Having re-looked at the shower of post #21, I now agree with your words. It’s the flow rate that is being adjusted to give a wide range of temperature outputs.
    However, there is a very big problem...
  9. Closed: Re: Regulating temperature of mains connected heating element: Skipping mains half cy

    Thanks, I also read the manual.
    There are three flow settings. Then there’s the temperature dial for you to increase/decrease temperature with whatever flow setting. The temperature scale has fine...
  10. Closed: Re: Regulating temperature of mains connected heating element: Skipping mains half cy

    sorry Betwixt, i should have made clear that i am only speaking of "electric showers" here.....you are kindly referring to whats known in shower company marketing departments as a "digital shower"....
  11. Closed: Re: Regulating temperature of mains connected heating element: Skipping mains half cy

    Interestingly, The following electric shower..
    https://www.mirashowers.co.uk/showers/electric-showers/mira-decor-dual-108kw/
    ..has an extremely fine resolution in its temperature setting, so it...
  12. Closed: Re: PIC1F1508 with four PWM outputs operating at different frequency?

    Thanks, oh no, we need some to be slower than others, thats why i was hoping that one of the pwm streams can have like a software flip flop put with it to make it say half the frequency
  13. Closed: PIC1F1508 with four PWM outputs operating at different frequency?

    Page 252 of the PIC16F1508 datasheet suggests that the four PWM outputs of the PIC16F1508 must all be the same frequency.
    However, is their some way that this can be changed?…eg one of the outputs...
  14. Closed: Re: Mains harmonic emissions for dimmable offline LED drivers.

    Thanks i see what you mean and agree.
    This does appear to be a mistake in the regulations though.......i mean, the customer may only need 25W at a certain time, but would have to use 50W...wasting...
  15. Closed: Re: Mains harmonic emissions for dimmable offline LED drivers.

    As discussed, the Class C regulations require conformance all the way down to 25W. However, as I have remarked, its not economically feasible to produce an offline SMPS LED driver of power >100W...
  16. Closed: Re: Mains harmonic emissions for dimmable offline LED drivers.

    OK thanks, ill look into adapting it for opto-isolated feedback.
  17. Closed: Re: Mains harmonic emissions for dimmable offline LED drivers.

    Thanks, but we are sure its Table 2, page 7 (class C ) standard for 25W upwards for lighting supplies...
    http://www.epsma.org/PFCver100406_b.pdf

    Interestingly, a Dual interleaved offline Flyback...
  18. Closed: Re: Mains harmonic emissions for dimmable offline LED drivers.

    Hi
    The attached LTspice simulations show a 97W PFC’d Flyback LED driver which passes mains harmonics at 97W…but when the dimmed down version at 29W is simulated, we see it fails on the 3rd...
  19. Closed: Re: interleved active clamp flyback converter circuit

    usually, a full wave rectifier would supply the input bus voltage needed by the interleaved active clamp flyback.
    You cant make a full wave rectifier with an interleaved active clamp flyback
  20. Replies
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    Closed: Re: current-mode boost converter UC3845

    Sorry no its temperature dependent.
  21. Closed: Re: Mains harmonic emissions for dimmable offline LED drivers.

    Thanks Volker…

    ..i hate to say it, but that is open to interpretation, and also, it says that it only concerns those conditions identified by the “manufacturer”, and not by the approvals body.
    ...
  22. Closed: Re: Mains harmonic emissions for dimmable offline LED drivers.

    Thanks, I would love to be able to afford these specs so i can read exactly what is said.
    The thing is, there is a question here which may remain unanswered, and that is the following....

    It is...
  23. Closed: Re: Mains harmonic emissions for dimmable offline LED drivers.

    Thanks for your quote. From the way that is worded, it does look to me that the mains harmonics are only to be tested at the maximum load. It talks about five equal dimming steps from min to max, but...
  24. Replies
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    [SOLVED]Closed: Re: EMI reduction using GTO

    yes it sounds like you are doing leading edge dimming.
    I think trailing edge dimming may be slightly less EMC noisy.
    You can also make the switched egde slower to reduce emc.
    If its say a dimmer...
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    170

    Closed: Re: Common mode choke DC circuit connections

    by the polarity dots on your CMC, i see that it is connected correctly....it is connected such that the field from the one coil, will cancel the field from the other coil, concerning diff mode...
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