Hot answers tagged

30

The block might be "piggy backed". A piggyback board is an extension or a daughter board. Thus in this case it means that the V35/X21 module is located on a daughter board. Here an example:


23

The reason the same symbol is sometimes used for TVS diodes (Transorbs) and Zeners, is a Transorb has a lot in common with a Zener. An ideal Zener and an Ideal TVS-diode would be indistinguishable in their characteristics. This leads to ... laziness in library management (or ignorance) and the same symbol is used. Regulator Zeners and TVS-Zener diodes ...


22

The USB 3.1 specification spells out exactly how to make this, and any other USB C -to- USB legacy cable. For a USB-A (2.0), the connection looks like:


21

The cathode of the LED must be connected to the ground not Vcc


20

The datasheet has a pretty thorough description of the use of the ADJ pin with \$R_1\$ and \$R_2\$: Since both \$R_1\$ and \$R_2\$ appear in the equation for the output voltage $$V_{\text{out}} = 1.25\text{ V} \times \left(1 + \frac{R_2}{R_1}\right) + I_{\text{ADJ}}R_2$$ you need both in order to realize an arbitrary output voltage. Depending on your ...


17

The short-circuit in red puts the 2 points A and B at the same voltage, bypassing the capacitor C2.


17

Overview I'll avoid depending upon algebra as an explanation. (Because algebra, while providing quantitative answers, doesn't often help people understand something unless they are very fluent with mathematics.) Regardless, it's still helpful to have the datasheet available. So here is TI's LM317 datasheet just to make it convenient when needed. The best way ...


17

It is a neutral grounding transformer with a secondary loading resistor to effect high-resistance grounding of that big (1220MVA) synchronous generator. It connects from the neutral (star point) to earth. The drawing is incomplete, it doesn't show the neutral side of the primary being connected to earth but it is in reality. The zero sequence reactance of ...


16

NS means "No stuff". This is an assembly instruction. Nothing will be placed on the PCB for C7. NS is yet another abbreviation along with DNL (do not load), DNP (do not populate), DNI (do not install), DNS (do not stuff), NOLOAD, OMIT. Related threads Why use "OMIT" components on a PCB? 'Not Mount' on PCB Design Why does there seem to ...


14

I agree with you that it is important to know the meaning of the different ways for using such symbols. And the same applies also to the voltage-to-current ratios (resitances, impedances). For my opinion the standard is (or should be) as follows: Uppercase (V,I) for DC and rms values Uppercase for ohmic resistors R=V/I Lowercase (v,i) for signals as a ...


13

That scheme is a fast-finder index for the schematic components. Figure 1. Instead of having to search the schematic coils, capacitors and resistors can be quickly located by scanning the index across the top. Two lines are allowed for each component type - but this is barely enough judging by the results. It's a nice system. For a long time now we have ...


11

Piggy or piggy board usually refers to devices (or small boards) which are plugged / soldered onto larger boards. For example, bluetooth uses 2.4GHz, which is really sophisticated stuff and could easily need more design work that the entire rest of the board. So there are small bluetooth modules of the size of a post stamp available, which can be soldered ...


9

"These N-MOSFETs will turn on with just 5v from the Arduino." Are you sure? Do you expect them to conduct 60A with an Fds of 0.05 Ohm with 5V at the gate? (Just checking your understanding of the datasheet. They will switch on with 5V at the gate, but they will do less well than with the 'normal' gate voltage of 10V.) But your top mosfets have a problem. ...


9

From Eagle help file 'Editor commands - LABEL':- Cross-reference labels If the optional keyword XREF is given, the label will be a "cross-reference" label. Cross-reference labels can be used in multi-sheet schematics to indicate the next sheet a particular net appears on... The format in which a cross-reference label is displayed can be ...


8

Any element for which terminals are connected by a conductor, as the capacitor in the figure, is said to be shorted. By having their shorted terminals, the voltage thereof is zero (more precisely, the potential difference between them), so that this element is not operational in the circuit, and can be removed for analysis. The other two capacitors are in ...


8

Your answer is incorrect in the sense that you produce an error signal from signals that have different physical dimensions. In your system, you subtract temperature units from volts, which is not a valid operation ("you can only subtract apples from apples"). The unit conversion in the feedback loop is missing. The answer in the book is actually pretty ...


7

Left terminal: Normally Open Center terminal: Common Right terminal: Normally Closed Confirm by measurement.


7

The 74HC04 will have power (Vcc) and Ground connections - often not shown in schematics. For the first diagram, with the switch closed, the input to the inverter will be grounded (at logic Low), and the output will be a logic High (we don't care what, if anything, is connected to the output). The 74HC04 is a CMOS part, and has a very high input impedance....


6

For momentary NC/NO switches, the one shown closed, is the one that should be normally closed. Convention follows common sense. The given switch though, is a on/on SPDT switch. It isn't really a NC/NO momentary switch, so there is no concept of "normally closed" aside from it being the side you want. If only one throw of a SPDT switch is used, the symbol ...


6

The circuit on the left can be called an "AC power transformer and bridge rectifier with load resistor". If you added the capacitor from the circuit on the right you could call it "AC power transformer and bridge rectifier with load resistor and smoothing capacitor". Here's what the circuit with the smoothing capacitor does: - And in more detail (but still ...


6

The "low" motor speed is instead realized by blocking every negative half cycle of the incoming AC with Diode 1. The "high" speed is realized by bypassing the diode. In this particular hair dryer the motor is never in series with the heating elements. I found your schematic particularly confusing, so I redrew it. In general, try do draw high voltage ...


6

The switch you have is almost exactly like the one in the top diagram, the only difference is there are two contacts for each position, plus it has a pair of contacts for the "off" position which you can also ignore. So you can just wire it up as follows: where the pin numbers 3, 4, and 5 correspond to the 3, 4, and 5 I have added to the circuit below: ...


6

Are E1 and E2 electrolytic capacitors and C1 and C2 Ceramic Capacitors? E1 and E2 are polarised. electrolytic capacitors. C1 & C2 are unpolarised & could be ceramic What is the value of C2? Is it 2.2 nF? and what is the meaning of /Y next to its value? The value of C2 is 2.2nF. The Y means the safety type of capacitor. X are good across ...


6

Figure 1. As suggested by the datasheet. The LM317 works by adjusting its output to be 1.25 V above the voltage at the ADJ pin. With R1 = 240 Ω there is a current of \$ \frac {1.25}{240} = 5.2 \ \text {mA} \$ running through it and R2. The constant current through R2 means that the voltage drop across it changes linearly with the resistance of R2. ...


5

From your question: "Why is C2 termed as short-circuited in this diagram?" it seems you are asking "What in this diagram indicates that C2 is short-circuited?" But in your comment: "... but why?...I couldn't understand it.", it seems you could be saying: "I (now) understand that it is short-circuited, but why is it short-circuited?" as in, it makes no ...


5

There is absolutely nothing strange there - it's just how they've drawn it that's strange. Let me re-draw it as a proper schematic for you: simulate this circuit – Schematic created using CircuitLab When the switch turns on the relay activates and power flows to the motor (depicted as a lamp here - circuitlab doesn't have a motor). Why did they ...


5

I'll add a couple of points to the good answers you've already received: quantities obtained applying various kind of transforms to the time domain signal should be uppercase, specifically: Phasors, i.e. complex representation of sinusoidal signals. Frequency-domain signals, i.e. Fourier transforms of time-domain signals. For example the frequency response ...


5

Here is a basic current transformer shown schematically and as a more physical construction drawing. Just two windings are shown here but three would be similar. Another convention is to list the number of turns as shown or with the letter "T" as in 1000T.


5

I recently laid a board out with the exact same relay + header arrangement. Due to the pinout of the relay the simplest way of routing the traces results in the pinout given by @RichardCrowley. Here is a render of the portion of the board with the relay header: And this is the PCB traces of that section: You can probably find the same trace layout on ...


5

It represents a bus or a set of parallel lines, and the value next to it is the number of individual lines.


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