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0

You can use some mind mapping software like FreeMind. It could help you to organize your collected information, ideas and references.


0

The voltage measurements will come out different if different voltmeters (True RMS or averaging) are used. The voltage coming off the wall-wart will not be sinusoidal when loaded with an ordinary rectifier. Anyway, I'd put in some heat sinks and save $ 590,-!


2

I agree with Oleg and Spehro's point about the PCB color. I think the soot on the cover is suspicious, however. Did you get the 19.5V power adapter voltage measurement under load? In any case, the input voltage does not exceed the spec. But their temperature calculation assumes 25 'C environment, which may be wrong, especially inside the box, and besides ...


6

I don't think there is necessarily anything wrong with the unit. Let me play devil's advocate here. The "charring" just looks like it might be some dirty air that got mixed around by convection currents. The PCB is not discolored such that it shows in the photos (maybe it does show on the bottom). If you measured the voltage with no load applied (just ...


2

The regulator looks normal to me. The PCB area around excessively warm part will noticeably change color, 5 years is long enough for this to happen if regulator was indeed overheating. The "soot" on the cover could be caused by outgassing; this happens to plastic at any temperature. It's not clear from your post what kind of help you require. The pictures ...


3

It may be that the power adapter used to power the device is not well regulated (a simple transformer) and your AC wall power is on the high side. The regulator circuit on the board might be designed without consideration of a high-line voltage. Adding a heat sink onto a power tab part like this is usually easy. There are many designs available that ...


1

If we can design a bit of a "silly" circuit, then the following would kinda work. (for one opamp) (Gain is not quite linear.) You've got to pick R4 to give a gain a bit more than 20... but I'm too lazy to work out the exact number. simulate this circuit – Schematic created using CircuitLab


0

Well, if you feed your signal into the pot you get a linear output level from 0 to 1 coming out - that sounds like a start. If you then buffer the signal before the pot you get >100k input impedance and, if you make that op-amp an inverting amplifier with Rin = 110k and Rf at 1.1Mohm you get inverting gain of 10. All that remains is to add a buffer op-amp ...


4

It depends on the opamp. In the old days when we had to trudge to school barefoot in the snow uphill both ways, opamps inputs drew enough current to matter to many circuits. For such opamps, the imbalance in current between the two inputs, called the input offset current was lower than the total current drawn by each input. You could cancel out the common ...


3

It it to mitigate the input leakage current of the OPAMP The OPAMP will attempt to keep the difference between + & - to equal zero. The input leakage current of the OPAMP in conjunction with gain resistors will produce a voltage at the - pin. If the + pin was tied to 0V there would now be an offset error voltage By providing a resistance to 0V (usually ...


1

R1 is there to counter-act any small DC offset since the integral of any DC offset tends to infinity. These offsets can come from source errors (your source may not be exactly a sign wave) or they can be intrinsic to the Op-Amp (known as input offset voltage). edit: oh wait, you're asking about R1, not R3. Incidentally, it amused me when someone up-voted my ...


0

First of all, unless you are willing to spend hundreds of hours and probably a thousand dollars (minimum) on this, it is not a good idea. Good news, since you won't be selling your board, you can get a hobbyist version of Eagle which is good for up to 6-layer 4" x 6" board for $169. Bad news, is because of all the surface mount components inclduding BGA, ...


0

Take a look at the OMAP processor from Texas Instruments. There's quite a lot of data available on those, compared to a lot of the ARM chips from other vendors. Nowadays, also the Broadcom processor which is used in Raspberry Pi has at least some public documentation, much because of Raspberry Pi. The core design for Cortex A is always similar: the ARM has ...


0

Since you're going from ~18 volts to ~ 4 volts, this should more or less work as a voltage regulator. In this role, 1) Change C2 to 0.1 uF - the LM7815 specifies operation at this output capacitance, and 200 uF may well cause it to oscillate. Better yet, try just the LM1815 with the 200 uF cap (not the rest of the circuit) and see what happens. I presume ...


5

There are many topics about this, and 99.9% of them say (paraphrased): "You are not good enough. Unless you have many many years in industrial professional board design for similarly complex embedded systems, start with Arduino and making your own (successfully), and perhaps go get a bachelors in Electronics Engineering and a few years experience at a ...


2

Sometimes you might use an FPGA because you have software that runs on a long-obsolete and unavailable physical processor that you want to resurrect. Whilst not pin-compatible (although DIP-style mounts have been seen) this lets you be cycle accurate. A pure software emulation on a commodity microprocessor is unlikely to be so. For example apple2fpga


9

There are several valid reasons for instantiating a microprocessor or microcontroller in an FPGA. Here are three: You just want to learn about the operation of a processor. FPGAs give you infinite ways to probe what's happening inside the processor as it executes code. This is just for learning. You are implementing a big system that requires the ...


10

If you just needed a microcontroller, and didn't have an FPGA, it would be unusual to use a FPGA with microcontroller firmware. However, not all projects grow in that direction. Many tasks have clear need for a FPGA, but eventually come across a task which really isn't suitable for a VHDL solution. Sometimes a problem is simply best handled by a general ...


11

In extension to the answers of Majenko and PkP: This trend of embedding a CPU into the FPGA design has lead to several heterogeneous systems like: Xilinx' Zynq-7000 family Altera's Arria/Cyclon/Stratix SoC FPGAs MicroSemi's SmartFusion FPGAs There is also an Intel Atom + Altera FPGA chip on the market: ...


23

Benefits: blazingly fast interface between the microcontroller and any custom interface or I/O logic on-chip. customizable processor and debug interfaces also, often easier control logic than writing the control code with, say, VHDL Downsides: Possibly more expensive FPGA is needed to fit both the microcontroller and the custom logic, compared to ...


24

If your project is going to use an FPGA for the grunt work, and it has the spare capacity, why would you go to the expense of an extra chip when you can just implement it in the FPGA? For many procedural control environments it can be considerably easier to implement the required setup in a language like C than trying to do it in VHDL or Verilog. By adding ...


2

Sadly there is no accepted standard. As with most schematics, whatever works to convey the information best for your group is all that matters. Each tool is also going to implement hierarchical designs in different ways. Altium for example, allows you to add suffixes to reference designators. One way for you to do it would be to have R1_1, R1_2, R1_3 .. ...


1

This sounds very much like a homework question to me but as its Xmas... Barry is quite correct if we were to consider every possibility but let us assume for this particular case that the question is actually solvable or at least approachable. i.e. the box contains only a few passive components arranged in a simple circuit. How could we approach it? ...


0

You can use a three input AND gate .Connect the A1 with a , B1 with b and C1 with c.Then connect the output with reset pin of 4026


0

You could very well likely add a pullup resistor to the +12V in the controller so that the controller can "see" the PWM signal from the sensor when the gauge is disconnected. You would have to do some experimentation to see if various size pullup resistors that you add will cause much change to the PWM signal when the gauge gets connected. If it does cause a ...



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