Questions tagged [reference]
The reference tag has no summary.
93 questions
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How precise is a DVM input impedance for high-Z circuit measurements?
I'm building a resistive probe using four 10 megaohms resistors to measure the output of a high impedance (> 2Meg)/high voltage bias supply without loading it too much. The idea is that the jury-...
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1
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64
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ADC measurements drop after exposure to noisy input
I have an ADS131M08 ADC that I am using to measure voltage in various positions in my industrial EV battery (all positions are above the highest cell, but at different points on busbars, before or ...
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0
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151
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Is my NEO M8N GPS design true?
I have always used GPS breakout cards until now. Now I want to use the same modules in another card that I have produced more professionally. I have obtained such a drawing with the drawings I found ...
0
votes
2
answers
495
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SuperNode when there is a reference node?
i just realize i solve this circuit:
The problem asks to find Va, Vb and Vc, so i used the concept of 'SuperNode' in the V1 branch and i it got solved right (Vb=-12V, Va=14V and Vc=4V) , but ...
- 285
1
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2
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150
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Should reference plane change its potential value if a track goes to another layer?
Assume you have a four layer board.
Signal
GND
Dielectric
VDD
Signal
And you having a track in the 4:th layer. Suddenly you're using a via to go through the 4:th layer to 1:st layer.
Question
The ...
- 1,466
0
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1
answer
264
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What is the recommended reference for modules on the schematics?
In my schematics I often use external modules like NFC readers, USB/TTL converters, MP3 players, and so on.
They are physically connected to the PCB with a connector (for example a standard 2,54 mm ...
- 1,593
1
vote
1
answer
83
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DDR3 U-DIMM Signal Reference Plain
I am doing the PCB layout of a DDR3 U-DIMM and I have run into a perceived gap in the JEDEC DDR3 DIMM standards and am hoping to get some input from a DDR3 SME who could clarify the Address/Control ...
- 37
0
votes
4
answers
831
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Buck converter with external reference voltage?
I would like to have a buck converter that takes in a reference voltage, and outputs the same voltage.
This is assuming that I'm giving it a Vin that's high enough to support the output voltage that I ...
3
votes
0
answers
143
views
Are there industry standards for incorporating a 10 MHz reference signal input into a design?
Are there any industry standards for accepting 10 MHz reference input signals into PCB designs? I've read about standard power levels (as in, 13 dBm at 50 ohm input impedance) in a few forums, but I'm ...
- 31
4
votes
3
answers
598
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Unstable voltage reference after changing DAC
I have developed a DAC-based signal generator board that I want to use to generate sine waves of different amplitudes and frequencies.
The board was working but unfortunately, the digital-to-analog ...
- 352
0
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0
answers
44
views
Constellation diagram of an 8-PSK modulator with \$\cos(\omega _ct)\$ as reference oscillator [duplicate]
For the figure and problem below, is my 000 input plotted correctly and has the correct phase angle in my constellation diagram?
The cos(ωct) is located on the positive x-axis since according to my ...
- 19
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0
answers
812
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Constellation diagram of an 8 PSK with a \$\cos(\omega _ct)\$ reference oscillator
Please help me with this problem in Tomasi's book for digital modulation. After getting the summer output, I got confused about what to draw in the constellation diagram.
According to my prof, since ...
- 19
0
votes
1
answer
172
views
Reference switch: which position and NC or NO?
I have a small linear axis, which is operated with a stepper motor.
I need a reference switch to determine the position. My question is, do I run this switch as normally closed or normally open?
Also, ...
0
votes
1
answer
88
views
RDS - PLC wires
I'm an American but I'm changing some of my drawings to RDS (Reference Designation System) to make these drawings more similar to the drawings of equipment that keep coming in.
What is the proper ...
- 183
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vote
2
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4k
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VREF pin of STM32F303
I am designing a custom-made board with STM32F303 MCU and some ADC chips. I have a question regarding VREF pin of the microcontroller. As far as I understood, its main function is to provide a ...
- 177
3
votes
1
answer
221
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Is there sufficient 'ambient hum' to obtain a 60/120 Hz reference wirelessly?
In a typical urban (USA etc) setting, we seem to be awash in 'powerline hum'. Has it been done, or could it be practical, to recover this to get a wireless reference for a battery-powered system, like ...
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3
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293
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Should ADC reference pin also be a kelvin connection?
Reasking this question with a proper schematic:
I am doing a ratiometric measurement of a Thermistor. The thermistor is located over 5 metres away from the ADC and all other components. This is going ...
- 361
-1
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3
answers
260
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CMOS active crystal oscillator output voltage uncertainty
I want to use SG7050CAN CMOS active crystal oscillator as reference input to ADF4106 PLL. The input voltage level is 0.8/AVDD Vp-p min/max.
Now, the SG7050CAN datasheet says, it's low voltage is 0.4 V ...
- 59
0
votes
2
answers
802
views
CMOS active crystal oscillator load capacitance, to be used for PLL reference
I do not have a clear idea of what load capacitance is. I am looking forward to use the ADF4106 PLL with a ~580 MHz VCO to synthesize the frequency.
For the reference input to the PLL, I wanted to ...
- 59
1
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2
answers
4k
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Can I mass-delete REFs from components in KiCad?
I have a PCB, and it can't nearly fit all of the REF markings on F.SilkS and B.SilkS. I want to just make my own for a few components, e.g. I would write "R1-R16", rather than "R1",...
- 223
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2
answers
2k
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Resistor in shunt regulator not following Ohm's law?
I was reverse engineering a power tool battery charger (21V SMPS) that derives its 5V rail from a simple shunt regulator, employing a TL431 programmable precision reference and a NPN transistor, as ...
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0
votes
1
answer
176
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Driving 18 Thermistors in parallel
I am designing a circuit that needs to have 18 thermistors to measure the temperature at various points.
The thermistors are 2metres+ away from the ADC
Usually when I power a thermistors I use a Vref ...
- 361
0
votes
1
answer
417
views
TP4056 custom PCB battery reference voltage
I have a custom PCB where I implemented BMS system based on TP4056 from a 5V regulated solar power source. Everything works as expected regarding battery charging and output but I am encountering a ...
- 155
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1
answer
140
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Driving Delta-Sigma ADC with reference clock output from MCU
I am sending out the PB clock (32MHz which is PLL multiplied) generated from the internal FRC on a pin to feed into an ADC as a master clock after probing it at 32MHz. This is what I see.
It doesn't ...
0
votes
2
answers
446
views
Which is better for an adjustable stable reference voltage output?
I have two methods of achieving this and am trying to decide which one will be a better option for a stable output. The supply voltage is a linear regulator output, so it is pretty much constant.
...
1
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1
answer
222
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Reference clock in FM receiver chips (si4735)
The datasheet is mentioning a 32678 Hz "reference clock" (RCLK) input.
It appears to be a well known thing in this type of ICs because it's highlighted in the list of features.
I guess ...
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1
vote
0
answers
95
views
How to connect a ENC28J60 or ENC424J600 to a KSZ8091 PHY and from PHY to an unmanged strapped configuration to a KSZ8863 or other switch
How would one go about connecting MAC chip to a PHY and then to a switch for dual ports for daisy chaining? Rather be a strapped configuration for use in unmanaged mode so no need for MCU software ...
- 21
1
vote
2
answers
212
views
[op amp - Gain current source - current reference]
I have a question about the formula to consider for calculation of the gain for the electronic bellow.
Thanks for your support.
- 197
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2
answers
1k
views
How to solve a LED-resistor parallel with a resistor?
Hi there I am curious as to how you would solve this circuit to know voltage drops and currents. It came about from a previous question I had asked which showed my understanding was not quite what I ...
- 37
0
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3
answers
84
views
Is there an equivalent EE term for "homeostasis"?
In biology, homeostasis is the state of steady internal physical and chemical conditions maintained by living systems.
Is there an equivalent term for a circuit or electronic device? So that would ...
- 7,967
0
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0
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156
views
Current mirror not depending on power supply (BANDGAP design)
is there any topology that allows a current to stay constant on a current mirror when the power supply of the transistor is varied?
I simulated a bandgap and the PTAT varies a lot when I the power ...
- 103
0
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2
answers
471
views
Opamp Current Sink + FET circuit help
I've been trying to figure out a design someone made for controlling a precision high current LED, and it's got me in a bit of a pickle. For the life of me, I can't figure out this exact op amp ...
0
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1
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759
views
Reference manual & Datasheet
I am new in the world of microcontrollers and I want to know the main differences between a Datasheet and a Reference Manual of a microcontroller and when do I use one and when the other.
1
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1
answer
166
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Question about feedback in a current reference
I'm studying the following Vbe-based current reference:
The author of my book says:
Observe that the circuit has two feedback paths around the gain stage. One positive, the other negative. Assuming ...
- 616
3
votes
3
answers
3k
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Self Biased Current Reference
I'm studying this circuit:
The author of my book says that the purpose of this circuit, called "Self Biased Current Reference", is to generate a current almost independently of the supply voltage. He ...
- 616
0
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1
answer
218
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STM32F429ZI reference voltage
I want to use the full output resolution of DACs (12bit) in the range of 0-1 Volt (and not in the range 0-3.3 Volt). I see there is a pin VDD in this board (STM32F429ZI), please help me to understand ...
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1
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93
views
Series voltage reference output voltage
What is output voltage of series voltage reference IC (for example MAX6100) when input voltage is below minimum input voltage? Is it zero volts, or something else?
Didn't find answer to this from ...
- 97
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1
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207
views
Wheel heading using PWM
I have a general question which im not sure how to implement.
Suppose that a car is driving on a straight road and it starts doing some maneuver.
Due to this maneuver the driver moves the wheel ...
- 137
2
votes
1
answer
884
views
Selecting the equipment with the optimal 10 MHz reference
In a larger testbench I have 5 synchronized instruments (signal generators, ARBs, VSAs etc). I am trying to decide which instrument to take as "master". I rule out the older/cheaper parts (Tektronix ...
- 1,362
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2
answers
3k
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10 MHz reference distribution (daisy chaining vs. BNC tees vs something else)
10 MHz is the quasi-standard for reference clock in measurement equipment. Most boxes have "REF in" and "REF out" or "10 MHz in"/"10 MHz out".
In my case, I have a measurement setup consisting of an ...
- 1,362
2
votes
3
answers
438
views
Create small variations in voltage for opamp reference pin
Hello and thanks beforehand.
I'm designing a circuit to measure 4 wheatstone bridges using 4 Analog Devices AD8422 in-amps. Now, i'm feeding the AD8422 output to a 3.3V ADC, so i'm offsetting the ...
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309
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AREF Voltage same as VDD but through a reference IC
My project has 9V and 3.3V on the board. I would like to use a precision voltage reference IC for the analog reference on the MCU (MCU powered by 3.3V).
The precision of the voltage reference IC is 0....
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3
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3k
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Copyright of reference designs?
I have been reading a design guide by TI which provides full schematics for their reference design seen Here.
There is copyright stamped all over this document as seen below. I don't plan on using ...
user160063
0
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2
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1k
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the voltage output and resistance of a potato
For an undergrad lab experiment on noise analysis in various electric power suppliers, I constructed a battery from a potato with Cu/Zn electrodes and measured the outgoing voltage. Now I want an ...
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3
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698
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How an op-amp determines its output without a reference point? [duplicate]
I was struggling to understand how an op-amp determines its output without a reference point.
The output of an op-amp is A * (Vni - Vi)
Then let's say we have an inverting op-amp with a gain of 1000,...
- 11
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1
answer
103
views
Measuring PSR of a current reference chip
Some Background:
I'm designing a test board to characterize noise and PSR of a multiple voltages(1V) and currents(1uA) reference IC. The chip has a single voltage source. I use ultra low noise MUX ...
2
votes
1
answer
111
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A mechano-electro-magnetical control circuit
I came up with the following mechano-electro-magnetical control circuit. The system as depicted here is in equilibrium, i.e. the upper spring s1 is relaxed , the upper circuit is closed (C1 producing ...
5
votes
1
answer
794
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What do decimal/alphanumeric suffixes after a slash mean in a schematic cross-reference?
I'm looking at a circuit diagram for the ChipWhisperer, which is a tool for power analysis and glitch attacks. You can grab the full circuit schematic as a PDF, but here's an excerpt:
What do those ...
- 11.5k
5
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4
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4k
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Capacitor after Voltage Reference "for stability"
I've got a lot of experience with rather "low-level" electronics (resistor networks, passive filters, basic op-amp circuits) and some experience with higher-level stuff like micro-controllers, but I ...
- 203
3
votes
1
answer
648
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How to connect a diy audio signal to my "expensive" audio interface
I'm a hobbyist and after some experimentation (around 4 years) I want to connect my signals I create on the breadboard to my expensive audio interface. Until now I was using the "mic" input on my ...
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