# Tag Info

6

There are lots of issues with using 3V directly. For starters, the forward voltage of an LED is related to the wavelength of light it produces, ranging from about 2V or less for red to about 3.6V or more for blue. So no single voltage is going to work for all three colours and devices that run from a single supply would have to be given enough voltage for ...

5

12V might be the "quasi" standard because of the 12V car batteries/electrics that were there years before the LED strips. Of course no one is driving the 3V led with 12V and a resistor directly. That would be too much loss. Since there exist DC/DC converters which can transform voltage with a good efficiency from one voltage to another, it does not ...

4

It may be easier to see if you break things up into functional groups. Here are the first few of these: simulate this circuit – Schematic created using CircuitLab Starting from the left, you have an unregulated DC supply providing $V_-$ and $V_+$ rails, followed by a (specialized) $5.0\:\text{V}$ zener/resistor pair that yields a continual ...

4

There are two sides in this question. One side is the Type-C connector itself, and the other is about wires along the cable. First, the Type-C connector dedicates 4 contact groups for VBUS and 4 for return GND. Therefore each contact carries only 1.25A, which is reasonable, and this is the solution on connector side. The second concern is about the cable. ...

2

The ESP8266EX datasheet (Table 5-1 on page 18) says that the maximum I/O input voltage is 3.6 V. Use logic level shifters.

2

In a simple configuration like this, there is a tradeoff between efficiency and accuracy. The forward voltage of each LED is slightly different, and it changes with temperature. If you are to run the LED strip at 3V, all LEDs must be in parallel, with no individual current limiting for each LED. That would lead to uneven lighting, and probably thermal ...

2

Most explanations disregard reactive power as "useless" power or power that we don't want to pay for. Such explanations are wrong. Sources of such information should probably be avoided. "Reactive power" is a common term for reactive volt-amperes (VARs). Reactive volt-amperes have one very important use, they provide the magnetic fields for every ...

1

Power Comes 10.267 KW, instead of 6.9 KW If the supply and load are balanced then the 3 phase power is 3 x 230 V x 10 A = 6.9 kW irrespective of phase rotation. Please review my calculations and tell me if I am doing something wrong. Because I did measure power through Three Phase meter, it showed the phase voltages as I calculated but overall power ...

1

I see where your confusion is, and I think what you're missing is that the bottom rail there is not labelled ground anywhere, and the non-inverting input is chassis-ground referenced. The inverting input has feedback from the output via R4-R5-R1.

1

If you just add up the rating plate values for every piece of equipment in the building, you will end up with a figure that far exceeds what you actually use. That's because you haven't allowed for "diversity". In practice, nobody turns every bit of equipment on at the same time, nor is everything running at full power all the time. You would be better ...

1

Don't separate planes unless you have a good reason to. Henry W Ott says there are very few reasons to do this. The most important thing that I can say about slots in ground planes, is don't have them! If you do have slots, no traces can cross over them. If a trace does cross over the slot ask yourself this question: Where is the return path for ...

1

PG&E is shutting off power to prevent lines blown together by winds from sparking fires My reading of that report suggests that PG&E also expects some damage to its power lines by the winds (and falling trees etc). This means that when it's time to restore power some consumers may be left without power until the repairs can be made.

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