Activity for Olin Lathropâ€
| Type | On... | Excerpt | Status | Date |
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A: Current Flow in the OFF Time of a Switching Power Supply It's not clear whether you are asking about what the capacitor does in a buck converter, or how a capacitor works internally. I'll therefore go with: I am having a difficult time picturing the flow of current and the role of the capacitor during the OFF time of a buck converter. At this level,... (more) |
— | about 4 years ago |
| Edit | Post #277844 | Initial revision | — | about 4 years ago |
| Article | — |
High/low indication of power supply with linear post-regulator System description This concept provides a simple high/low indication for the output voltage of a power supply that is followed by an LDO (low drop-out) linear post-regulator. A basic diagram of the system is: Image The method presented here is particularly useful when the power supply is a... (more) |
— | about 4 years ago |
| Edit | Post #277550 |
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— | about 4 years ago |
| Edit | Post #277550 | Initial revision | — | about 4 years ago |
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A: LED with a parallel resistor You haven't provided any context, so there is little to say about this particular design. For all we know from what you told us, this could be homework from a student that just made a mistake. However, I have put resistors in parallel with LEDs in real professional designs. In all cases that I r... (more) |
— | about 4 years ago |
| Comment | Post #277547 |
What is the context? Where is this schematic from? How do you know it isn't just a bad design? (more) |
— | about 4 years ago |
| Comment | Post #277541 |
@Lundin: Right, but as I said, those are all in bank 15. (more) |
— | about 4 years ago |
| Edit | Post #277541 | Initial revision | — | about 4 years ago |
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A: How come the registers in a micro are application specific? Calling those "registers" might be technically correct, but rather misleading in my opinion. These are really RAM locations. Probably for historical reasons, Microchip refers to RAM bytes in some of its microcontrollers as "registers" sometimes. Change "Complete Register List" to "Complete Varia... (more) |
— | about 4 years ago |
| Edit | Post #277467 |
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— | about 4 years ago |
| Edit | Post #277467 | Initial revision | — | about 4 years ago |
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A: Why RC toys still operate in 27Mhz band? Roughly around 27 MHz is the old "CB" (Citizen's Band, 11 meter) frequency block. The advantage of this band is that it is free to use with limited power. This is the band "walkie talkies" used to use. I remember back in the 1970s a bunch of us neighborhood kids had walkie talkies. You could si... (more) |
— | about 4 years ago |
| Edit | Post #277391 |
Post edited: Deleted greetings and the like. |
— | over 4 years ago |
| Edit | Post #277418 |
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— | over 4 years ago |
| Edit | Post #277419 | Initial revision | — | over 4 years ago |
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A: 4-Layer PCB Routing Question 1 - Signal 2 - GND 3 - PWR 4 - Signal This seems to be common advice, especially on the 'net someplace, but that doesn't make it good. Stop and actually think about what problem you are trying to solve with each layer. What exactly do you think dedicating a whole plane to just power will do... (more) |
— | over 4 years ago |
| Edit | Post #277418 |
Post edited: Deleted greeting. This isn't a kafeeklatsch. |
— | over 4 years ago |
| Edit | Post #277401 | Initial revision | — | over 4 years ago |
| Answer | — |
A: Bypass Caps and High Frequency Current Return Path First, let's be clear about something. All currents partially take all paths relative to the inverse of the path impedances. It's not an all or nothing function. This "Takes the path of least resistance" is often heard, but really not the best mental picture. For example, if a voltage is applie... (more) |
— | over 4 years ago |
| Edit | Post #277316 |
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— | over 4 years ago |
| Edit | Post #277316 | Initial revision | — | over 4 years ago |
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A: Constant Current Load Circuit with Op Amp Assuming nothing is broken or wired incorrectly, this is most likely the result of the opamp oscillating wildly. The average may still be about what it should be, so you might not notice with only a meter. Put a scope on G and S of Q1. Oscillation should be no surprise, since it's quite possible... (more) |
— | over 4 years ago |
| Edit | Post #277272 |
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— | over 4 years ago |
| Edit | Post #277279 | Initial revision | — | over 4 years ago |
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A: Darlington or Sziklai configuration - why and when using complementary pairs? Why do the Darlington or Sziklai configurations need complementary transistors? They don't. In fact, it's usually not even desirable. However, before we get too far, let's make it clear what we are talking about: Image In this example, both constructs result in overall NPN polarity. I'l... (more) |
— | over 4 years ago |
| Edit | Post #277272 | Initial revision | — | over 4 years ago |
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A: Complementary transistor pairs - what is the point ? You generally want complementary NPN/PNP pairs when they are used as opposites of each other in the same circuit. One transistor is usually used with opposite polarity as a mirror image of the other. For example, consider this circuit: Image Q1 drives the output during the positive half of ... (more) |
— | over 4 years ago |
| Edit | Post #277271 |
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— | over 4 years ago |
| Edit | Post #277164 | Initial revision | — | over 4 years ago |
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A: Amplifier compensation with added resistor across opamp input terminals Here is the circuit in question, with the component designators changed to make them easier to write: Image To understand this circuit, try building it up in pieces. First, let's only include R1 and R2. The circuit is then a basic non-inverting amplifier with a gain of (R1 + R2)/R2. Now ... (more) |
— | over 4 years ago |
| Edit | Post #275955 | Post edited | — | over 4 years ago |
| Comment | Post #276117 |
@tim: You should ask that as a real question. (more) |
— | over 4 years ago |
| Edit | Post #277030 |
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— | over 4 years ago |
| Edit | Post #277048 |
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— | over 4 years ago |
| Edit | Post #277048 |
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— | over 4 years ago |
| Comment | Post #277048 |
@coq: I misunderstood your R2. I thought you were trying to model the leakage due to the broken insulation. (more) |
— | over 4 years ago |
| Edit | Post #277048 |
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— | over 4 years ago |
| Edit | Post #277048 |
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— | over 4 years ago |
| Edit | Post #277048 |
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— | over 4 years ago |
| Edit | Post #277048 | Initial revision | — | over 4 years ago |
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A: How could a damaged wire in split-phase power delivery create these voltages? Here is a basic diagram of the power feed to your house, according to what the power company said they found: Image R1 represents the additional series resistance due to the cable being corroded. R2 represents the leakage current to ground due to the broken insulation. Both these can vary ove... (more) |
— | over 4 years ago |
| Comment | Post #277032 |
@coq: I'm an opamp kind of EE, not electrical power engineering. I do have an explanation that I think makes sense, but I was hoping one of the electrical power folks would jump in. I just got to a good break point in my day job work, so maybe I'll post my idea soon. (more) |
— | over 4 years ago |
| Comment | Post #277032 |
I think this is a good start, +1, but I disagree that the leakage is to L1, not ground. I think there is more to it than you show. (more) |
— | over 4 years ago |
| Edit | Post #275955 | Post edited | — | over 4 years ago |
| Edit | Post #275955 | Post edited | — | over 4 years ago |
| Edit | Post #275955 | Post edited | — | over 4 years ago |
| Edit | Post #275955 | Post edited | — | over 4 years ago |
| Edit | Post #275955 | Post edited | — | over 4 years ago |
| Edit | Post #276765 | Post edited | — | over 4 years ago |