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2
votes
3answers
266 views

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 ...
3
votes
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 ...
1
vote
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, ...
2
votes
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....
0
votes
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 ...
0
votes
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 ...
0
votes
4answers
905 views

Cascaded XOR gates function for F

What is the function for F exit in this scheme?
2
votes
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 ...
0
votes
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
1
vote
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 ...
1
vote
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 ...
0
votes
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 ...
11
votes
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 ...
4
votes
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 (...
4
votes
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 ...
1
vote
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 ...
3
votes
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 ...
4
votes
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 ...
0
votes
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 ...
9
votes
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 ...
1
vote
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 ...
2
votes
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 ...
2
votes
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 ...
1
vote
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 ...
1
vote
1answer
3k views

Calculating Quiescent base current

I am given a question relating to a bipolar junction transistor. The information I am given in the question is shown below. I am first asked to select a quiescent point from the graph to find \$V_{...
9
votes
6answers
52k views

What are the pins for in this Relay module?

I am trying to figure out how to use this relay module. There is no datasheet that I could find for the whole module, there however are for individual box. Here is the picture below, there are three ...
7
votes
4answers
2k views

How does this quartz antenna work?

I picked up something called a quartz antenna at a surplus store for $2.75 so I could tear it apart. This is what I found: There were two small cardboard boxes filled with loose quartz crystals ...
0
votes
2answers
3k views

300 amp 12vdc power supply on a standard(American) wall outlet

I am building a project that will draw around 300 amps at 12vdc, for about 40-60 minutes then it will rest for a few minutes. For this projects application it will be very impractical to build a ...
4
votes
2answers
185 views

Battery recharge protection for a dual-power ATtiny board

I have a small board with ATtiny85 and it has a button cell battery socket on it. The battery that I'm using is CR2032 rated 3V. At the same time, while programming it there will be second power ...
1
vote
0answers
78 views

Internal pull up resistors in a micro-controller vs external pull ups [duplicate]

Micrcontrollers such as PIC describe their pull up resistors as weak pull up resistors, what does weak signify? When/why would I want to use external pull-up resistors on I/O pins that support ...
3
votes
3answers
916 views

Boost DC voltage converter for wireless temperature sensor (1.5V to 5V)

I'm trying to design a wireless temperature sensor powered by one (or maybe two) rechargeable NiMH AA cell(s). The sensor should read and transmit the temperature every couple of seconds and remain in ...
1
vote
1answer
1k views

If I'm using an RTC and ATMega328p (arduino UNO chip), do I need two crystals?

If I'm using an RTC that requires an external crystal, do I need a second external crystal for my ATMega328p? Or can the two share? What is standard practice for this kind of thing? I'm making a ...
7
votes
5answers
8k views

Why peltier elements have smaller heatsink on cold side?

I have seen in nearly all configurations that Peltier elements are mounted with huge heat sinks on hot side as compared to tiny ones on small side. Is this just a way of explaining the need of heat ...
14
votes
1answer
12k views

How do NAND flash memory writes work?

Below is a picture of my understanding of NAND flash memory operation. NAND flash works by first erasing all the cells in a single block (essentially setting it to '1') and then selectively writing 0'...
1
vote
1answer
87 views

Adding a router (no key) to an encrypted Zigbee network

Backstory: I'm looking to extend the range of a proprietary wireless system. From looking at diagnostic data I think it uses a 2.4GHz ZigBee network, propably Mesh configuration. It might not be ...
6
votes
1answer
10k views

Car battery desulfation procedure

I have some old ~100Ah car batteries. There is no mechanical damage, they were not overcharged or incorrectly used. I assume they are sulfated. This is a theory from Wikipedia: Pulses must last ...
1
vote
2answers
544 views

PID Parameters effect while tuning

We aways find lots of materials which explain various methods of tuning a PID controller. Also, it is not hard to find out what are those parameters. Once I've read that P and D parameters, in general,...
0
votes
1answer
558 views

op amp level shifter no input situation

I tried out op-amp level shifters on web. The ones recomended here as well but there is a problem when no input applied. The output voltage is no seperable from the case voltage applied. As i ...
2
votes
2answers
191 views

How can I keep my sinusoid in phase with its input after filtering?

A section of a circuit I'm working with makes a sinusoid from a square wave by passing it through an 8th order filter (MAX293). Up until now, everything was ok, but I was told recently that the input (...
-1
votes
1answer
195 views

MOS differential pair question? [closed]

If \$ V_{GS} >V_t\$, then the MOS transistor is in the triode zone, therefore isn't working as an differential amplifier.I understand this.Only when the transistor is in the saturation zone, MOS ...
5
votes
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"...
4
votes
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 ...
1
vote
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 ...
3
votes
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 ...
0
votes
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 ...)?
3
votes
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 ...
5
votes
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?
0
votes
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 ...
1
vote
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, ...
1
vote
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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