cowboydan
  • Member for 7 years
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Rules and guidelines for drawing good schematics
17 votes

Here's my two cents 1. Break it down Break down your design into modules. Put a block diagram of the system on the first page of the schematic 2. Answer who, what, where, when, why Who - For each ...

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Amplify Microvolts up to Volts
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5 votes

You can definitely do it with op amps. Some things worth investigating A 'T' feedback network in the op amp Be advised of the issues with that much gain in an op amp. You will need to account for ...

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Does NFC drain power if tag is attached constantly?
Accepted answer
5 votes

The answer is yes. The reader (phone) has to scan continuously to see if it is there. Even if this does not happen at the hardware level, it would be possible to continuously "ping" the reader coil ...

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Best practice for documenting ports / peripherals?
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4 votes

The short answer is "whatever makes sense to you and the rest of your team". Since that isn't very informative as far as how to implement something, ultimately communicating the intended behavior is ...

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How does a receiving antenna generate current/voltage?
4 votes

For reference, check out books by Balanis. They are THE reference on antenna design/theory. This is a very good question and is key to fundamental EE principles. To help visualize this, let's ...

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Why do serpentine traces (supposedly) entail decreased ESD immunity?
4 votes

On page 18 of the referenced document, it mentions that long serpentine traces can contribute to radiated EMI and decreased ESD immunity. As for the radiated EMI portion, this may be due to the fact ...

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ESR of Ceramic Capacitor
3 votes

The ESR equation works so long as you are below the resonant frequency of the cap. If you take a look at the impedance "notch" curve, the ESR should decrease up to the point where the cap is at its ...

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I2C PCB Layout Considerations
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2 votes

Wihtout knowing the constraints of your board real-estate and existing layout (i.e. is this a new design where you have free-reign, or must you shoehorn in I2C). One technique I've had success with ...

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Electronics can fail due to overheating, overvoltage, and mechanical stress. Are there other causes?
2 votes

Temperature: Temperature can do a number of things to cause the circuit to fail, such as If you have ceramic capacitors that have a certain dielectric (i.e. X7R) and the environmental temperatures ...

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Current sourcing octal buffer/line-driver for 7+1 segment LED multiplexing?
2 votes

In the "for what it's worth" category, this resource I found below lists quite a few latching constant-current LED drivers (8 and 16 bit). http://www.altera.com/literature/an/an286.pdf Some of them ...

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Why are watts used as a measurement for some appliances?
2 votes

A very practical explanation for the outlier (the drill) is because the drill uses a battery pack (see the black handle in the bottom of the picture in your original link). The juicer runs off of ...

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How can I sense if a cane is being held upright or fallen down?
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2 votes

I agree with one of the above replies in that you need something (probably two accelerometers) to detect the angle at which the cane stands (calibrated at the factory if you are industrializing this). ...

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Why do LEDs have a maximum current?
2 votes

Here's another way of looking at what some others have said: The conversion of current to light is not 100% efficient, so the remainder of the energy not converted to light is heat. Each electronic ...

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Microcontroller shutting off because of brief loss of power, can a capacitor fix this?
2 votes

It is good practice to have some capacitance placed CLOSE to the power pins of the microcontroller. Typically a 1uF and a 0.1uF in parallel would do it. This is a general guideline though. It depends ...

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Do all/most SOIC chips whitstand the 235 degrees C for reflow soldering?
1 votes

Any reputable device in their datasheet will have (in case you are not familiar) a "Solder profile" that indicates not only the peak temperature, but also the ramp-up temperature rate, dwell ...

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How much RF-interference does a typical desktop computer produce? How much does a metal case without windows reduce it?
1 votes

If you look on the chassis you should see the compliance rating class. Class a or b for instance. This will lead you in the right direction to see what the maximum allowed emissions would be for that ...

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Inserting Capacitor into CIrcuit causes LED to fade - Why?
1 votes

Your capacitor is connected in series with the LED instead of in parallel with the anode. The "fading" is the AC coupled impulse from connecting the battery to the capacitor. Capacitors block DC ...

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PIC 24F output port not clearable
1 votes

I'd recommend that you check the datasheet and see if there are any errata associated with that particular micro. From what I know (in the past), the case used to be where I would have to read/...

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How much faster would optical computation be?
1 votes

I studied optical computing in undergrad. From that, certain categories of problems would be solved MUCH faster. For instance, do some research on 4-f optical correlators. These kinds of operations ...

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What is the best solder type in terms of health?
Accepted answer
1 votes

Tin silver is ok. Just make sure you do any of this in a well ventilated area. Look for RoHS compliance lead-free solder if that is what you are asking. And don't eat it :)

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How does the Arduino compare to PIC and AVR for serious learners
1 votes

If you want to program microcontrollers, you need to learn (if you don't already know) 'C' and arguably some assembly language. Arduino is good if you just want to get something working (i.e. want ...

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How much power can a 74HC4066 switch (for LEDs)
1 votes

To answer your question with your current approach (total current sink capacity), you will have to pay attention to the safe operating area (SOA) of the device. The datasheet you referenced has ...

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Help Trobleshooting my first solderless circuit on a breadboard
1 votes

First off - good for you on getting this project going. This will be the first of many. Looking at the LEDs, I can't see how they are plugged in, but the leads should not be on the same row going ...

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Design of Op amp given transfer function
1 votes

Well you have three poles in your equation and one reactive element in your circuit, so you need two more caps. Also, I'd refer to Ron Mancini's "Op Amps for Everyone" for reference on op-amp ...

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How a zener and a schottky diodes protect laser diode?
1 votes

You'll want to use something faster than a Zener for ESD mitigation like a transient voltage suppressor (TVS). The zener isn't fast enough to react to the human-body-model discharge rate of an ESD ...

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How do I design a circuit to replace two LEDs (which illuminate alternately) with one bicolor LED?
1 votes

For example if you want to build something like a model railroad crossing signal, you could design what's called a relaxation oscillator with a 74HC14 hex inverter, a resistor and a capacitor. This ...

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MOSFET broke after attaching capacitor bank
0 votes

If you are interested in an inrush limiter circuit, Texas Instruments makes one that has an evaluation module on Mouser here. The datasheet for the TPS2491 takes into account (funny enough) power ...

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measure instantaneous position of a solenoid piston?
0 votes

One method would be to add a rack and pinion to the solenoid plunger. The pinion could move an encoding wheel that people less a photo interrupter to determine absolute position.

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Why wont my 3volt LED light up with two 1.5volt Batteries?
0 votes

Check the datasheet for the LED. To put the LED into conduction the supply voltage must exceed the forward voltage of the LED (Vf_max). This is specified in the datasheet. Without enough potential to ...

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How do I provide constant voltage to a load?
0 votes

There is no "constant voltage" in practice as there will always be some noise or ripple on it to a varying degree. The current draw is not constant for the microcontroller (and is missing from your ...

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