# All Questions

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### Grounding between enclosures in a closed system

Currently we are developing enclosures in an isolated "system of systems". Our overall system is fed AC power and converted to 28V with an off-the-shelf converter. Currently the enclosures we are ...
3answers
525 views

### What happens when you fall off the end of main() in a PIC? [duplicate]

Another question included this program: void main(void){ TRISD = 0x00; PORTD = 0xFF; } Let us assume that it does exactly what was intended up through ...
1answer
107 views

### Can this dimmer really handle 144W?

I was looking for a dimmer to control an LED strip with following characteristics: 5 meters long 14,4W (max) per meter, so 72W in total 24V I found a dimmer on ebay that says it can handle 144W, ...
0answers
5k views

### Shielding effectiveness calculation

From The Basic Principles of Shielding: Apertures, or holes, have SE. The SE of an aperture and ultimately the entire electronic enclosure is determined by the size, shape and number of the apertures....
1answer
337 views

### Stepper Control using DC Brushed Motor Driver

Is there any way to control a bipolar stepper motor using one or more DC brushed motor drivers? My only interface to the motors is setting an integer to represent their speed, ex -100 to 100. I ...
3answers
115 views

### Signal to noise ratio for a non-physical property

The signal to noise ratio for a voltage, current, or power is easy to understand, but how do I calculate the SNR when the signal is not a physical property, but instead an abstract quantity? I'll try ...
4answers
905 views

### Cascaded XOR gates function for F

What is the function for F exit in this scheme?
2answers
2k views

### Checking if microchip or software is broken

I've build a circuit with a pic18F4550, I'm trying to power up 8 leds, but I get no output voltage from any output pin. I suspect the pic might be broken because while building the circuit I made two ...
1answer
107 views

### pwm or gpio for pled display on beagle bone? [closed]

Wondering which adafruit bbio library i should use. I know nothing. My sense is that GPIO will be simpler to communicate the display info to the screen. The screen is a 128x32 adafruit pled
1answer
503 views

### Anyka AK1120Q - 'Mobile Application Processor', Spy Cam, cheap cam-corder?

I've been trying to learn more about my spy-cam. I opened it up, and found that it has a Anyka AK1120Q IC. I found a datasheet for the: AK3671B but it took a lot of searching. Why is it so hard to ...
1answer
142 views

### Short NMOS differential pair amplifier question?

In my book it says that in the NMOS differential pair: $$V_{G1}=V_{G2}=V_{CM}$$ But does not explain why. Can you please explain to me why the voltage in each gate is equal to the common mode ...
2answers
117 views

### Is it possible to detect cellphone IDs in an enclosed area

I'm working on a project where I need to be able to identify different cellphones in an area. Ideally I need a way to identify when specific cellphones enter and exit a range - this could be IMEI or ...
2answers
10k views

### Why doesn't shoot-through occur on totem-pole structure?

I'm designing a totem-pole by BJTs in order to drive a MOSFET. I studied on several online examples and built up my circuit according to what I understood from them. However, there is a detail which ...
5answers
2k views

### Object detection using sensors and then reporting the location

I am trying to prototype a sensor + location reporting chip that will do the following: Sense if a object is present over the top of it (a vehicle to be specific) Reporting the location of the chip (...
3answers
3k views

### What are the failure mechanisms in an integrated circuit?

Context I've always tried to design my circuits for chips to be well within their absolute maximum ratings. However understanding the failure mechanisms is vital to be able to debug a chip when ...
1answer
763 views

### Can a Solenoid be driven from one of the pins of a Servo controller?

Would it be possible to operate a solenoid (e.g. this Plastic Water Solenoid Valve - 12V - 1/2" Nominal, suggested for use with "a TIP120 or N-Channel power FET with a 1N4001 kickback diode to drive ...
2answers
14k views

### How do I calculate what resistors I need for RGB LEDs with 3.7V? [duplicate]

I have a total of 4 x RGB LEDs. I am hoping to power these as well as a RFduino BLE module with a 3.7V lithium rechargeable battery. I was just wondering how I would go about calculating the ...
3answers
4k views

### What will I see in oscilloscope when attempting to analyze Bluetooth or Wi-Fi signals?

I would like to know what will show up if I put bluetooth or wifi carrier signal (2.4GHz family) in a say 50MHz oscilloscope? Am I going to see something like a rectangular block? And the only ...
2answers
332 views

### In logic levels, why are both the driver and receiver needed?

Here is what my textbook has to say about logic levels: The mapping of a continuous variable onto a discrete binary variable is done by defining logic levels. [...] The first gate is called the ...
1answer
3k views

### How can I safely prototype a mains power circuit?

I'm building a device that has a mains power component, which I need to prototype before building to make sure everything works. I know I need to make sure wiring—and insulation!—is thick enough to ...
2answers
138 views

### PID controller of a known system model

When we know the impulse response of a system, we know all the equations needed to find an output of the closed loop system. So, theoretically we can find the perfect or at least a very good PID ...
3answers
550 views

### Can you safely “short circuit” 2 signals when they compete for the same pin to avoid having to use a multiplexer?

I'm developing for a very limited, 8 pin LPC810 microcontroller and have to connect multiple signals on a single pin. Obviously, if there's only 1 output signal on a bus, that should be OK, but what ...
1answer
421 views

### MCP41100 Power supply and grounding ? Analog ? Digital?

I'm thinking of using an mcp41100 digital potentiometer to control an op amp gain. My board will have a split ground plane - digital and analog grounds. Unfortunately the mcp41100 doesn't have ...
3answers
889 views

### Convert 3.3v to 14v?

I want to use a 4D Systems OLED display with an ATmega32u4 based PCB. I'm still working on designing the PCB and have hit a problem. In the data sheet it says that one of the power supply pins for the ...
1answer
3k views

3answers
843 views

### Dump Flash Memory through a single GPIO pin

I'm working with Infineon's XMC4500 Relax Kit and I'm trying to extract the firmware through a single GPIO pin. My very naive idea is to dump one bit at a time through the GPIO pin and somehow "sniff"...
1answer
1k views

### Does this circuit regulate current?

I am being told that the circuit below will regulate current, I am wondering how true that is and how exactly does it do it if so. As far as I can tell: two NPN transistor with their bases biased by ...
3answers
1k views

### Question about thevenin circuit analysis with voltage across voltage source

I have a certain circuit in mind and I want to find its Thevenin equivalent resistor: I see that there is an dependent voltage source so I add a voltage source of 1V between a and b and make the ...
2answers
3k views

### Loop count in a current transformer

I was reading this article about current transformers. It says that, the loop count is 1 when the wire is just passing through the core. And there are 2 loops when it is wound for once, and 3 loops ...
1answer
91 views

### Variation of the amplifier input impedance by the temperature

I have a question, How can I calculate the input impedence in amplifier when the union base-emitter temperature is different (25C 100C, 50C ...)?
6answers
7k views

### Heat sink, how much does fin and base width matter?

I have lot of aluminum sheet 0.5mm thickness at home, normally heat sinks that I have seen had 1mm thickness. Now I am wondering should I get that sheet welded as heatsink or do I absolutely have to ...
2answers
1k views

### Why don't solar cells produce visible light when supplied with electricity?

... A cursory Google search didn't reveal an answer... Is the energy conversion a one-way process?
2answers
3k views

### Stepper motor failing. Electrical interference?

Update: This question is already so long, I'm hesitant to add to it but it occurs to me to ask if electrical interference between the stepper motor wires could cause this sort of behavior (motor ...
1answer
364 views

### PID controller modelling

According to the following simple PID control system: (source: umich.edu) We could create the equation: $$(R(s)-Y(s))C(s)P(s) = Y(s)$$ Wich will lead us to $$\frac{Y}{R}=\frac{CP}{1+CP}$$ So, ...
1answer
738 views

### IMU angle computation error

I am using MEMSENSE nIMU for getting only the Euler angles. However, i have a problem in the following case: When i try to rotate the IMU randomly and return to the initial position (i.e. lying ...

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