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Questions tagged [analog]

Analog circuits have a range of voltages, rather than just two as in digital logic.

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130 votes
5 answers
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Why does Samsung include useless capacitors? [closed]

I do component-level repair of tablet mainboards, and I have seen this puzzling situation on two different models of Samsung tablet mainboards so far (SM-T210, SM-T818A). There are ceramic chip ...
Crash Gordon's user avatar
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40 votes
13 answers
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Why can current only flow in loops? [duplicate]

In the following image: Why can't current flow across the following wire? It's a simple question, but I've kind off always wondered. Thanks!
Physco111's user avatar
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40 votes
6 answers
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Designing a *linear* MOSFET driver stage

I'm looking for a MOSFET driver circuit that can be placed between an op-amp and a power MOSFET to operate the transistor as a linear amplifier (as opposed to a switch). Background I'm developing an ...
scanny's user avatar
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39 votes
6 answers
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Is analog signal arithmetic faster than digital one?

Would it be theoretically possible to speed up modern processors if one would use analog signal arithmetic (at the cost of accuracy and precision) instead of digital FPUs (CPU -> DAC -> analog FPU -> ...
zduny's user avatar
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38 votes
5 answers
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Can I use the analog pins on the Arduino for my project as digital?

I am new to using Arduino, and I have an Arduino Uno. For the projects I've done, I've only used the digital pins. I am building a small vehicle that uses stepper motors. I have run out of pins to ...
bogen's user avatar
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37 votes
2 answers
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Weird resistor with dots around it on the schematic

I was looking through the LTC4041 datasheet and saw this: The 10mOhm resistor with the two nodes really close to it - is that a "special" resistor or something? Why have they drawn it like that?
AlfroJang80's user avatar
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36 votes
6 answers
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How do digital oscilloscopes achieve such high sample rates?

From the perspective of data capture, how is this achieved? If I wanted to implement a home-made digital device to capture high frequency analogue signals, what are my options? So far, I've only come ...
Jodes's user avatar
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34 votes
7 answers
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Are there any Analog FPGAs?

As I understand it FPGAs are flexible "digital" circuits, that let you design and build and rebuild a digital circuit. It might sound naive or silly but I was wondering if there are FPGAs or other "...
Ali's user avatar
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29 votes
9 answers
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Why are op amps used so frequently in analog electronics?

I've read in several books and papers the observation: "Op amps are the bread-and-butter of analog electronics", or "... op amps are the most commonly encountered building block in analog circuits ..."...
scanny's user avatar
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29 votes
3 answers
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Why does VGA have so many ground pins (compared to DVI-I for example)?

If you look at the pinout for VGA, there are several ground pins: I was curious as to why, and I found this answer. To sum it up, the extra ground pins are so that each pin has its own ground in ...
user112513312's user avatar
28 votes
4 answers
2k views

How much data could be stored on a standard compact cassette using modern encoding?

My father and I recently dug out his old Commodore 64 from his basement and tried to revive it. Among other accessories, we also found his old Datasette drive, which is essentially a normal tape drive ...
DLCom's user avatar
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26 votes
3 answers
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How do I extend the number of analog (input) pins available to me?

I already know how to extend the number of digital pins on an Arduino using a multiplexer. I want to increase the number of analog input channels that I have. One solution is to add another Arduino ...
Manishearth's user avatar
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24 votes
6 answers
5k views

In earlier tape recorders, how was tape spool angular velocity adjusted?

Tape recorders that use spools of magnetic tape transfer the tape from one spool to another as the tape plays/records. The spool with less tape must be rotated faster than the other. Here is such a ...
quantum231's user avatar
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23 votes
3 answers
2k views

Is twisting a single ended signal with its own GND really useful?

I know that the most robust way of transferring an analog signal over long distances is via differential pairs which are twisted together and then shielded (shield grounded at one end only). But ...
user42875's user avatar
22 votes
3 answers
48k views

How does data travel inside a wire?

I know this is a very basic question but the answers returned by google are way too complicated for me to understand. I am not asking about modulation here. What I want to know is what exactly is ...
Sunshine's user avatar
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22 votes
2 answers
783 views

Which way does electricity power a circuit?

Working with some circuits this summer, I ran into what everyone eventually does: Current flows from + to - despite the electrons flowing (well, bumping into eachother) from - to +. I understand the ...
Tom's user avatar
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20 votes
5 answers
3k views

Why is this meter giving different readings depending on its orientation?

My newly-restored (re-capped) 1950s vacuum tube voltmeter is now operational...but there's one further issue. The meter gives correct readings when lying on its back, but when oriented vertically- as ...
Simon Owen's user avatar
20 votes
5 answers
3k views

What is the true circuit behind an opamp?

So, first year EE student, and I just learned about op-amps. I understand the ideal model, and know how to analyze them, and understand the idea behind them/the circuit that we were shown that is ...
Mahmud Ahmad's user avatar
20 votes
5 answers
39k views

Inverting buffer with op-amps

I know that it's easy to make a unity gain buffer with an op-amp (as a voltage follower): simulate this circuit – Schematic created using CircuitLab I also know that it's easy to make an ...
Greg d'Eon's user avatar
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19 votes
2 answers
44k views

Input impedance of Arduino Uno analog pins?

I'm using the ACS712 hall-effect based current sensing chip on some small robotic arm motors, and reading in the analog voltage with an Arduino Uno. I've had reasonably good results, but only after ...
user avatar
18 votes
4 answers
4k views

analog circuit design resource recommendations [closed]

What are some excellent resources related to advanced analog circuit design? This includes RF, sonar, audio, low-frequency, high power, low power, noise, amplifiers, etc.. To get the most obvious ...
18 votes
5 answers
9k views

How can one make an analog voltage memory circuit?

I am looking for a circuit that can, on input, remember a certain voltage and output that voltage indefinitely even after the input has been taken away. The circuit should not change its output until ...
user2640461's user avatar
17 votes
5 answers
2k views

Can ULN2003 be a poor-man’s matched diode array?

I have a log/anti log application that requires “slightly” matched diodes - something better than you get just by grabbing a bunch of 1N4148s from a bin. I need the matching to be across each group of ...
Kuba hasn't forgotten Monica's user avatar
17 votes
8 answers
2k views

How can you turn perceived brightness (log scale) into a linear analog output using an LDR?

This question is not about how to make illuminance (in lux) a linear function of voltage! It's about linearly representing the human perception of brightness, which itself scales logarithmic to the ...
Niklas E.'s user avatar
  • 298
17 votes
5 answers
39k views

how determine the RC time constant in PWM digital to analog low-pass filter?

I 'm looking for the best RC time constant and its reason in a PWM to convert digital signal to analog based on duty-cycle and frequency and other parameters. PWM frequency is 10 kHz.
azin's user avatar
  • 371
17 votes
2 answers
3k views

Mixed signal PCB layout for PSoC

I am developing a PCB for an analogue sensing application. It uses the internal ADC on a PSoC3. As usual, the application is very space constrained (11mm x 21mm), so I have had to make some ...
Rocketmagnet's user avatar
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17 votes
2 answers
1k views

How to find the problem of this old Marantz amplifier?

After a first question referring to resistor symbols, I'm back with this old Marantz PM-68 class AB amplifier and I will refer to components using their ID that can be found in the service manual. ...
MFlop's user avatar
  • 455
16 votes
5 answers
4k views

Op-amp inverter followed by buffer. Why?

In a schematic I've been trying to understand I came across this sub-circuit: It's an op-amp inverter directly followed by a buffer. VIN comes from a DAC in a microcontroller and this circuit ...
mcmayer's user avatar
  • 327
15 votes
5 answers
8k views

Why isn't there any 9.5 digit multimeter or higher?

Why can't you buy a 91⁄2-digit multimeter? Isn't there any need for it? Is a 81⁄2-digit multimeter the latest high end you can buy? I have tried Keysight, Keithley, and Fluke, but there is nothing ...
voltage_drop's user avatar
15 votes
6 answers
48k views

How are positive and negative feedback of opamps so different? How to analyse a circuit where both are present?

In an opamp, feedback on the positive input places it in saturation mode and the output is of the same sign as V+ - V-; feedback on the negative input places it in "regulator mode" and ideally Vout is ...
Mister Mystère's user avatar
15 votes
3 answers
2k views

What do moving rails (voltage shifting on the rails) do to an opamp?

Since I've spent a good portion of my career trying to get opamp's rails as steady as possible at their intended voltage, I haven't really spent any time thinking about what would happen if the rails ...
Voltage Spike's user avatar
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15 votes
3 answers
8k views

What's the highest precision achieved for an ADC?

I was browsing Digikey the other day (don't you?) and I stumbled across some 32bit ADCs, there were offerings from Linear, TI and Analog. One stood out, the AD7177 from Analog which states in Table 7 ...
Sam's user avatar
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15 votes
5 answers
1k views

Analog analog multiplication, part of a hybrid CPU (for fun)

Short version: How do I make an analog multiplier that takes two analog DC inputs? Long version: I made a comment recommending Ben Eaters videos for another question, while doing so I ended up ...
Harry Svensson's user avatar
15 votes
5 answers
2k views

Which CMOS logic families can safely be used to construct linear circuits?

I've just learned that digital CMOS inverters can be configured to perform analog functions (most notably oscillators and amplifiers). However, many of the examples tend to favor old CD4000-series ...
Caleb Reister's user avatar
15 votes
2 answers
3k views

How do I size the output capacitor for a DC bench power supply?

I'm designing a DC bench power supply and have come to the matter of choosing the output capacitor. I've identified a number of related design criteria, but I'm finding my reasoning still going a bit ...
scanny's user avatar
  • 6,992
14 votes
3 answers
2k views

Why does digital equipment have more latency than analogue?

Is the explanation that the digital equipment takes longer to propagate? For instance, a software synthesis is very slow compared to a hardware synthesis.
Niklas Rosencrantz's user avatar
14 votes
2 answers
54k views

analogRead(0) or analogRead(A0)

The arduino reference states that you would use the following code to read the value from analog pin #5: int val1 = analogRead(5); However to read from digital ...
Tyilo's user avatar
  • 377
14 votes
2 answers
2k views

Share bypass capacitors with ICs or not?

I have a board which has many of the same IC MAX9611. According to the datasheet it should be bypassed by parallel 0.1uF and 4.7uF caps. Now I have like 15 of these right next to each other: I am not ...
Dumbo's user avatar
  • 3,234
14 votes
3 answers
98k views

What is Q-point of transistor?

What is the Q-point of a transistor? Why it is needed? How can we set this Q-point of transistor? Please explain it as I am having difficulty understanding this concept.
Ali Khan's user avatar
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13 votes
7 answers
7k views

Is it possible to send multiple data bits on a single wire at once?

Is there an existing protocol or modulation method where multiple data bits are sent over a single wire at once or maybe an additional ground line (like serial communication)? I know there are ...
CrownedEagle's user avatar
13 votes
13 answers
4k views

What is physically happening when there is a square wave input on the left plate of a capacitor and open circuit on right plate of a capacitor?

Mathematically I understand that through KVL that the output in the first image will match the input square wave. I am trying to understand physically what is happening. How is the voltage ...
maldingRookie's user avatar
13 votes
5 answers
2k views

Is it good practice to substitute a resistor by parallel and series-ing them?

In our electronics (I) lab they told us to never use resistors in parallel or series and choose a value near your calculations. but never explained why. Is it ok to just buy the range of 1ohm to 1M ...
mk safavi's user avatar
  • 157
13 votes
4 answers
3k views

General question about analog and digital signals

Newbie alert: I am not an electrical engineer, nor have I ever taken electrical engineering, so please bear with me. Whenever I read about the distinction between digital and analog signals, a ...
so.very.tired's user avatar
13 votes
6 answers
3k views

Why do we get only one frequency as output in oscillators?

I am just into oscillators where I learned \$AB=1\$ for sustaining oscillations in positive feedback. Since \$A\$ and \$B\$ are both frequency-dependent, \$AB=1\$ is true only for a particular ...
Souhardya Mondal's user avatar
13 votes
3 answers
2k views

Is it possible to reverse engineer an analogue IC from a physical example?

Lately I've been investigating custom ICs developed by Roland in the late 70s/Early 80s for their analogue synthesizers. They stopped manufacturing these components around 1989, there are no ...
blarg's user avatar
  • 453
13 votes
3 answers
5k views

Understanding bootstrapping in analog active filters

"Bootstrapping" is a common technique in (analog) active filters, where the output of the filter is fed back to a node that would otherwise be connected to ground. For example, the Sallen ...
nibot's user avatar
  • 1,680
13 votes
3 answers
2k views

The Pin 1 Problem in Audio, Star and Mesh Ground, and Contradictory Grouding Practices in Audio and Digital Systems

I recently came across the concept of "Pin 1 Problem" known in the pro-audio electronics. It seems straightforward at first, but becomes confusing when it comes to grounding. Let me describe ...
比尔盖子's user avatar
  • 5,234
13 votes
5 answers
2k views

Which is the preferred approach to PCB layout for signal vs power traces in analog circuits, and things to consider?

I have had to layout 2 layer PCBs several times now for analog signals, and am just beginning to learn the process. I often face a similar question in one form or another with regard to laying out ...
teeeeee's user avatar
  • 765
12 votes
4 answers
22k views

How can I slow down the switch time of a MOSFET?

I have an NMOS that is switching too fast for my application. Into the gate I am sending a logic-level square wave (PWM). Unfortunately for me, as expected, the output is also a near square wave. How ...
hassan789's user avatar
  • 2,096
12 votes
5 answers
8k views

More than one button in the same pin

I'm doing some project and I'm using Arduino to prototype, I have to use 10 pushbuttons (along with more things) and I don't have enough pins. One solution I could think of is to use the analog pins ...
MyUserIsThis's user avatar

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