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  1. NiGHTS

    AC to ADC design question

    I think what you are trying to convey to me is that if I don't use a driven reference on the non-inverting input, the op-amp input bias current that occurs when the inverting input switches it's polarity could in turn cause the simple voltage divider at the non-inverting input to momentarily...
  2. NiGHTS

    AC to ADC design question

    Dana, I appreciate that you took the extra time to double-check my design. Unfortunately you seem to have made a mistake reproducing it and then offered an inferior alternative to my most recent proposal. To be more specific, the simulation you claim to be of my design has an arbitrary 1.6V...
  3. NiGHTS

    AC to ADC design question

    Alright, I see it now. Actually, my math was wrong partly from that confusion with the schematic inconsistency. But looking more carefully at the documents mentioned in this thread showed me what I was doing wrong. So I've finally arrived to the solution: This worked correctly in both...
  4. NiGHTS

    AC to ADC design question

    You can, yes, as well as eliminate the initial voltage divider, but the vref would need to be 30V in my case, as far as I understand it. And if that's the case, I'd be better off using two op-amps because it would be cheaper to use a second op-amp gate and a tiny reference-level negative voltage...
  5. NiGHTS

    AC to ADC design question

    ¡Estoy muy agradecido, mi hermano! I think I'm becoming more clear on the concepts, so here is my latest circuit which at least according to a simple simulator seems to do the trick. Now for my rationale. Your vref circuit is very useful, and certainly works as intended without the need for a...
  6. NiGHTS

    AC to ADC design question

    This doesn't seem to work either. And to simplify this even more as a debugging strategy, I tried removing the op-amp just to see if the inputs produce an addition of any kind. It does not... I've also tried this in a simple circuit simulator with and without an op-amp, using that specific...
  7. NiGHTS

    AC to ADC design question

    I am trying to build a simple interface circuit where a signal input of about 30VAC can be converted to a range that can be safely processed by an MCU's ADC input pin. Here is a sketch of a schematic I came up with that might perform this conversion, but I'm not sure if it will work. I built...
  8. NiGHTS

    How can I remove the underling waveform from a signal

    I have a live device I am studying with a two channel oscilloscope. There are three locations where I can touch the probes which I have labeled A, B, and C. When the probe is placed in A you would see a reliable repeating waveform with clean lines. Though the shape is unique and not sine it is...
  9. NiGHTS

    How to work with Zener diodes?

    I'm sure this is an easy problem to solve but so far I'm perplexed with how to use a Zener diode for the purpose of generating a reference voltage for a differential comparator when a certain voltage is not known or no other reliable voltage available. Attached is an image showing the basic...
  10. NiGHTS

    Transient Voltage Supressor (TVS) Operating Voltage

    What occurs between the TVS Operating Voltage and the Breakdown Voltage? If the breakdown voltage is supposed to be approximately where any breakdown of the reverse current occurs, then wouldn't the operating voltage rating simply be arbitrarily chosen by the manufacturer? Speaking more...
  11. NiGHTS

    Power Regulation Strategy

    Well as long as this improves the heat output of the bridge rectifier circuit I'm all for it. When I click that link I see 1000uF on the page. Either way I agree this was the wrong part for the job. What you explained sounds like (A) on the following diagram. I'm used to measuring current in...
  12. NiGHTS

    Power Regulation Strategy

    My input voltage would be at most 30VAC and would include a bidirectional TVS right at the input (not shown in the schematic). Would this configuration along with Schottky diodes still seem risky to you? This is the one that was overheating...
  13. NiGHTS

    Power Regulation Strategy

    I have noticed that Bridge rectifiers have a generally high voltage drop across their diodes (1V) compared to the Schottky diodes. Should I use four of those instead of a bridge rectifier in order to lower the heat demand on the AC inputs? Also, do you have any advice on the capacitor selection...
  14. NiGHTS

    Power Regulation Strategy

    Actually I am familiar with this concept, but I didn't think to associate that to parasitic problems with a circuit like this one assembled on a breadboard. Since you are taking about such an infinitesimally small scale of frequencies likely manifesting as a very weak influence operating on a...
  15. NiGHTS

    Power Regulation Strategy

    I can't visualize where in my circuit there would exist frequencies that high running through the breadboard. Do you mean slight fluctuations in power line noise and such originating from inside the PWM chip? If you don't mind me asking, how does switching speed play a part in heat efficiency...
  16. NiGHTS

    Power Regulation Strategy

    I would normally worry about this for very high frequency applications, though since I'm running this gate at almost 100kHz I suppose this should be more of a concern to me. At what frequencies would you be worried about capacitance and inductance using a breadboard? Duly Noted. So the...
  17. NiGHTS

    Power Regulation Strategy

    I needed quick proof of concept. I am aware that breadboards are not designed for the load I am passing, but its far easier to experimentally reconfigure layout and part values with the breadboards and I try not to have it run for long periods of time. I am also aware of the importance of...
  18. NiGHTS

    Power Regulation Strategy

    Here's a quick update. I've built a breadboard prototype of the schematic I presented in this thread and it seems to regulate voltage correctly. The main problem seems to be with the diodes. They get extremely hot with voltages greater than 17V, and that in turn drops the voltage and current...
  19. NiGHTS

    Power Regulation Strategy

    The schematic was inspired by the one in the Datasheet for UC3573N, page 4. I did not include the sleep function as its not applicable to my project. Some of the gaps in their design were filled by this Datasheet for a similar part of the same brand. Unless I can successfully reverse engineer...
  20. NiGHTS

    Power Regulation Strategy

    They are part of the time, though if the math were done it would probably show that a lower amp diode would be fine depending on the duty cycle. I base this on the conceptual understanding of the function of the diode which is to complete the circuit on the load during the time when the MOSFET...
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