Tag Info

New answers tagged

0

Precision should be thought of in terms of significant digits, not decimal places, if you consider decimal places as being to the right of the decimal point. For instance a reading of 125Vdc has 3 significant digits of accuracy, while a reading of .002Vdc has only one significant digit of accuracy. If the real value were .0024Vdc your reading would be off ...


1

The problem of when to make an approximation is one of the reason engineering is not only an (applied) science, but it is also an Art, as engraved in the title of one of the most authoritative books on the subject: The Art of Electronics, Horowitz and Hill. This means that an engineer uses a lots of rules of thumb when designing something and these rules of ...


1

In theory, an ideal silicon diode may have a voltage drop of 0.7V. But it's difficult, if not impossible, to make all real-life diodes with the same part number, with exactly the same voltage drop. So all parts are accompanied by a data sheet, which typically spell out the minim, typical, and maximum values for a particular parameter. Note in this table, ...


2

I would suggest Apple chose magnetic induction charging for two reasons. Firstly aesthetics, no unsightly connector and secondly practicality since connectors can deteriorate get damaged and are a potential site for moisture ingress.


1

The purpose of the 4017 IC in this circuit is to "remember" whether the relay should be on or off. If you control the relay using software in a microcontroller (an Arduino, Raspberry Pi, etc), then you can simply store that state in a variable in the program instead. The 4017 IC is used here as a one-bit toggle-able memory and can be replaced by the ...


0

I've used Tango - but that must have been over 12 years ago, and was probably on Windows XP. If it won't run on Win 8.1, I'd assume it is a 16 bit program. Use Windows Explorer to open the folder that contains the program (tango.exe). Right-click the .exe file, and select Properties. A 16-bit program does not have a Version tab in this dialog box. Windows ...


0

You can solve this by placing in series an 'ideal diode' device such as ISL6146A. ISL6146A By using a FET as described you prevent voltage, down to 1V per the device datasheet, from reverse biasing anything before the external FET. However because of the body diode voltage would always pass through. If this is undesirable, a second FET in series with the ...


6

As Ignacio pointed out there is a parasitic body diode inside the regulator from the output to input. If VBUS has a very low source impedance then the C15 will get charged quickly through U5 and there is not much limiting the current. Or, anything connected to the VINLDO input could draw current from VBUS through U5 (for example, shorting to ground could ...


5

It is safe to apply a voltage to the output of a LDO regulator provided that it is not higher than the input voltage. Many LDO regulators have a parasitic diode from the output to the input that may become forward biased if the input is at a lower voltage than the output, thereby allowing a potentially destructive amount of current to flow.


3

Quantum231 - I do not fully understand what you really want, because: The four types you have listed are NOT different filter topologies (functions) - instead, they are 4 different approximations to an IDEAL lowpass response (and they can be transferred to corresponding highpass and bandpass approximations); All these filter functions can be realized ...


6

A filter topology, whether it's a passive one like a pi-section or an active one like the Sallen-Key circuit, is just a way to produce some poles and zeros. Generally, you can tune the circuit values (resistances, capacitances, inductances) to move those poles and zeros around in the s-plane. A filter design, like Butterworth or Chebychev, is a choice of ...


2

Chebyshev, Butterworth, Bessel and Cauer (Elliptic) approximations are not strictly implemented as active filters. They can be made passive as well, with insertion loss, but that isn't relevant at the moment. All they are is transfer functions. For a given corner frequency, each approximation will have a slightly different transfer function, but their ...


0

Well I would really stop bieng nosy in the physics involved(though its unclear why one wanna charge object to medium breakdown condition and stop due to arching and start all over again) Here where you can get started,you can apply many type of ionization sensor,some of them are very simple like pressurized Helium(much better option here) tube and PM tube ...


3

While using the x value in a simulation might be used to identify unexpected behavior, such a statement will not make sense if you synthesize your code to a gatelevel representation. And one-liners might be pretty, but they make the code more difficult to read. Also, the constructs may not be correctly identified by the synthesis tool, resulting in ...


4

There is a far neater way to make a multiplexer, using a vector. Example: module mux( input wire a, input wire b, input wire c, input wire[1:0] sel, output wire y ); wire [3:0] mux = {1'b0,c,b,a}; assign y = mux[sel]; endmodule In this case you assign your outputs into the variable 'mux' and then the output will be the sel'th element in the ...


7

Oops. I got the order wrong in my original explanation, and have edited to reflect this. My apologies. In your picture, Q5 and Q6 are being used as zener diodes. Current flows through the CB junction, which behaves as a reverse-biased diode. Since an NPN transistor has two PN junctions back-to-back, with the base grounded it looks like simulate this ...


0

Usually, when you encounter EAGLE for the first time, your biggest challenge will be to find foot prints for the most commonly used parts such as - Resistors, Capacitors, Voltage regulators, etc. I have compiled a small list of most commonly used component libraries in Eagle, it will help you to get started with PCB design quickly. ...


2

Efficiency A regulator can't improve the efficiency. [I have to reconsider this. I need to think about the buck.] A regulator will have losses. A regulator will have quiescent current (which varies a lot from one regulator model to another). Safety A regulator can prevent over-voltage of the downstream circuitry. However, there are other ...


0

All the answer you have received are very good. However,there is one other aspect that I feel has not been addressed. Your and your company's reputation. In my case, I would prefer to "err" on the side of "robustness." The reason being that I would gain a reputation for designing circuits that work reliably under varying conditions, and my company would get ...


2

It depends on how robust you need the design to be. Engineering is all about tradeoffs. If you want the design to be maximally robust, then your approach is correct. I'd go even further and apply a fudge factor beyond the datasheet min/max values, unless you know a lot about how the manufacturer arrived at those values. But doing that has a cost - in ...


0

Designing a device that will work if components have any combination of behaviors allowed by their data sheet is a good practice when it is practical. Unfortunately, many data sheets fail to specify device behaviors with sufficient detail to make that workable. As a simple example, suppose one takes a 74HC374 and wires outputs Q0-Q5 directly to inputs ...


9

I will do an worst-case analysis of circuits where the component values may have a significant effect on the performance of the circuit; for example the gain of a op-amp where that gain is important to the next circuit connected to the output of the op-amp. And I will do the same analysis for a switching power supply so I can expect the voltage(s) to be ...


7

I think that the strategy that is best to follow depends on the kind of product you're designing. If it's something simple and non critical, just an implementation of a circuit on the datasheet of an IC. Then probably your colleague's approach is good enough. The IC and other components are guaranteed to work over what is specified. Not much need for an ...


45

Engineering is not only about creating robust designs, but is about creating a design that meets some specifications. Usually young designers don't fully understand that economic factors are part of the specification. The problem is that sometimes those economic factors are not well specified (that's often a management's fault), but a good designer is ...


18

I'm with you 100%. That said, there are things (for example hFE) where you have to trust that things don't go too wonky between (say) two guaranteed points and that nothing in the physics and typical curves would suggest any kind of weird behavior. If you using a cut-and-try approach, which may actually be the practical way to deal with complex parasitics ...


0

I'm guessing your question deals with the paradox where the voltage across the capacitor can't change instantaneously, but the resistors are shorted to the voltage source and the capacitor and the voltage across them can? The voltage source and the capacitor have some resistance because they aren't ideal (as do the wires, but that isn't included in the ...


0

Initially, the discharged capacitor looks like a short circuit. All current will be flowing through it and none through the resistors, meaning that the voltage across all three devices must be 0V. Only once the capacitor has started charging will there be any current flowing through the resistors due to the voltage across the devices becoming non-zero.


4

Have a look at the image on this page. It's one of the representations which are clearer on how the IC works. I'll reproduce the image here: You can clearly see that the voltage divider is independent for any pin of the circuit (well, except Vcc and Gnd). So the 1/3 and 2/3 voltages are just derived from there, but the actual comparison is done by two ...



Top 50 recent answers are included