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Questions tagged [input]

Something put into a system or expended in its operation to achieve output or a result

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0
votes
3answers
475 views

ATMega input buffer

What happens if a AVR ATMega controller is doing something else when a input arrives on one of the serial ports? Does it has some sort of input buffering? I was thinking of using ATMega328 or simalar ...
1
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6answers
2k views

How can I build a simple USB signalling device?

I would like to construct a simple device that plugs into a USB port and sends the computer a signal (i.e just a 1) when a user presses the button or switch etc. I ...
3
votes
2answers
775 views

Clamping diodes or TVS

When should be clamping diodes preferred over one-directional TVS for input sanitation? Consider only digital inputs, not power lines. Clamping diodes seem to be recommended so I worry I might be ...
1
vote
2answers
554 views

Detect 220Vac signal on Microcontroller

I'm developing a module and the control switch may be at long distances. Considering I have the 127 or 220Vac input, I want to use that for switch signal. I believe is better, instead of making a ...
2
votes
3answers
2k views

impedance matching for Guitar input

What is the main difference between mic input and a guitar input? is it only the source impedance seen in the input of the amplifier? I am designing one pre-amplifier in which i need to input both ...
1
vote
0answers
548 views

P-MOSFET based automatic power selector

I have designed the attached power selector circuit, it has a 12V input and a 15V input, and should prioritize the later. It operates in three different scenarios: 1- 12V source R76+R79 divider ...
0
votes
0answers
130 views

PIC18 port b interrupt on change is very sensitive

I am running a stepper motor with my PIC18F46K80 microcontroller. This microcontroller offer me the port b interrupt on change feature which basically generates an interrupt if the state the port b ...
0
votes
1answer
349 views

What's the difference between all of these video inputs? [closed]

Over the years and with the large variety of hardware I've dealt with I've used quite a few of different video inputs and outputs. While I usually have no issue just plugging cables into devices, I ...
0
votes
2answers
469 views

12V Signal -> Relay -> Voltage Regulator -> Arduino mega analogue input. Will this work?

I have a system that sometimes generates a 12V signal to a DPDT relay coil, which switches on a 12V connection through the relay pins that can be used as a boolean signal to the arduino. I plan to do ...
0
votes
1answer
183 views

Connecting two different microcontroller outputs together to drive a single device?

I am interfacing with an existing product. This product uses a PIC16F54 uC and is ultimately driving a solenoid. This device is a black box to me and I have no input into the software running on the ...
6
votes
3answers
795 views

How CRT allows use of ligh-guns or pens etc?

While reading about CRT on Wikipedia, an information (CRT Allows the use of light guns/pens; https://en.wikipedia.org/wiki/Cathode_ray_tube#Advantages_and_disadvantages) suddenly triggered a a vast ...
1
vote
2answers
188 views

ATMega32u4 output power to input without external resistor?

I am new to electronics and have a SparkFun Pro Micro clone with an ATMEGA microcontroller. I wanted to know if I could set one pin to be an output that sends power to another pin that I have set as ...
5
votes
2answers
765 views

Diode Clamp failing with LDO Circuit

I'm back with yet another mystery. Summary question: Why would an input to a voltage clamped circuit de-stabilize and or elevate that voltage clamp's upper rail? How do you properly clamp voltage ...
1
vote
1answer
187 views

Read a common digital output from multiple digital inputs

I'd like to read a single digital output with two separate systems, each of which has a digital input. Both systems have a common ground. In principle, since the digital output is low-impedance and ...
0
votes
5answers
200 views

How to check 4 inputs and set flag in Microcontroller

I have a PIC MCU and have 4 input pins. I need to check the status of inputs and set the value of flag. Like if input 1 is active, then value of flag should be 1, if input 1 and input 2 are activated ...
2
votes
2answers
4k views

How to make clamping circuit to clamp exactly at 3.3 volts

I am building a circuit that attenuates the signal and sends it to 3.3V ADC, so I need to limit max voltage to 3.3V. After testing out some circuits for clamping the voltage(various schottky or zener ...
1
vote
4answers
9k views

What do these dashed/dotted lines mean in this power cord schematic, and how should I ground this device?

--Edited at Sparky256's suggestion for better clarity-- Background Information I'm making a power cable for a piece of obscure, surplus military equipment (an AN/UGC-74B teletype, to be precise). I ...
0
votes
3answers
343 views

Strange IC input leakage current

I am reading the datasheet of the HEF4894BT. First I saw the input clamping current is rated at 10mA and than I saw the input leakage current would be 10mA, too. I thought the input clamping current ...
0
votes
1answer
2k views

Controlling a single phase AC fan with a 0-10V DC input

I have a fan motor which is a permanent split phase single phase capacitor motor: http://uk.rs-online.com/web/p/axial-fans/2781543/ I currently control this fan's speed with the following controller:...
12
votes
4answers
2k views

Is this clamping voltage divider for a high-impedance input a good, robust design?

I have an AC input as follows: Can range from ±10V to at least ±500V continuously. Runs from roughly 1 Hz to 1 kHz. Needs > 100 kΩ of impedance on it, otherwise its amplitude changes. May ...
2
votes
1answer
354 views

Why is my pull-up resistor not working?

here's my schematic. I've got this circuit hooked up to those pins. Q1 is P-channel MOSFET (AO3401A), I've also got an ATmega328P not pictured, and POWER_BUTTON is connected to PC4 of the ATmega328P, ...
0
votes
1answer
69 views

Comparator input below V-

I am searching for a way to use a comparator with possible negative voltage on its inputs. My thoughts and attempts so far: Op amps and comparators with V+, V- and GND: the circuit utilizes a ...
0
votes
1answer
195 views

Amplifier IC - selecting input (Sound Card/Phone jack) and output(Headphones/RCA)

Good evening guys! I'm trying to figure out the solution to my problem, that I have encountered, but I just can't find anything close. So, first of all, the situation: I'm trying to build a 5.1 ...
1
vote
2answers
127 views

Impulse Response of a circuit

The following periodic function, \$x(t)\$, is the input to a linear, time-invariant system The impulse response of this system is $$h(t) = \frac{\sin t}{t} $$ which I converted to $$H(\mathrm{i}\...
0
votes
2answers
98 views

Impulse Response of a LTI system

The input to a L.T.I. circuit is \$x(t) = 6\cos(t)\cos(3t)\$, and the impulse response of the circuit is $$h(t) = \frac{\sin(3t)}{3t}$$ Obtain an explicit expression for the output y(t) as a function ...
0
votes
1answer
115 views

Programmatically switch betwean ground, power, signal for input port

I have this idea on creating a Atmel-based board with PS/2 connector for testing of old keyboards. So I'm looking for a way to assign 5V, ground or signal to each pin of the connector after board ...
2
votes
4answers
7k views

How to make a Karnaugh Map with “don't care” inputs?

I know that don't cares mean that it doesn't matter whether it is a 0 or a 1 and when don't cares are just outputs I can kind of understand how they work. But I am having a really hard time ...
0
votes
1answer
1k views

PWM input specs of Hobbywing Quicrun WP-1040 ESC

What are the controlling input specifications of a Hobbywing Quicrun WP-1040 Electronic Speed Controller (ESC) for brushed motors? I assume it should use the standard PWM with 1 kHz frequency as ...
0
votes
2answers
727 views

Common mode voltage elimination at differential pair receiver

Can you please explain to me how is common mode voltage of differential pairs is eliminated at receiver side? For example, if on RS422/485 bus there is more different transceivers (drivers and ...
0
votes
2answers
698 views

Updating outputs in PLCs

For all PLC manufacturers, is Mass I/O copying the choice for updating outputs? I found that there is another possible method: the continuous I/O updating. Can anyone tell me what is the reason for ...
0
votes
4answers
483 views

How to increase number of micro-controller inputs?

I have relatively little experience with electronics, but do have a basic understanding. I am attempting to build a measuring device, which will measure 100 points in 0.1 seconds. These will all ...
0
votes
1answer
76 views

How to understand rail to rail input circuit?

I watched an input circuit for ground rail as follows, Why do I have to place a current source here? If I place a resistor instead, there will still be current flowing in emitter-base direction for ...
1
vote
2answers
235 views

Same pin as output and input

In the 7447 BCD to 7-segment decoder chip, pin 4 is BI'/RBO'. That pin acts both as input and output. I would like to understand how exactly the internal circuitry works to make this possible. On page ...
0
votes
2answers
367 views

Is Input Offset Voltage perfectly proportional to output

Is Input Offset Voltage perfectly proportional to output in an opamp? Such that if one where to enter 0V differential to the +V and -V inputs, the output would be A*Input_Offset_V. Also, when using ...
0
votes
1answer
364 views

class AB amplifier input resistances

I was wondering if you could help me out, what would be the effect of changing R1 & R2. I have looked online, but mustn't be searching in the right place! My guess is that you would adjust them to ...
0
votes
2answers
73 views

Detect position of walkers along a path using IR transceivers

I am working on a project that the position of people walking along a path needs to be known. I'm a hobbyist so I don't know what options I may have. I want to use IR sender and receivers to ...
0
votes
1answer
765 views

input current vs output current

My old/new laptop adapter specs as given below. I understand the output current for new is 4.5A which is OK when compared to old which provides 3.25A load since it can provide more load. However, ...
0
votes
1answer
55 views

reduce sensitivity of digital input

I have a battery (3v coin cell) powered device with a digital input to a microcontroller. There is a pull down on the input of 10k. It is connected to a switch outdoors which, when off, could have a ...
2
votes
4answers
486 views

Unstable input to trigger LED after 10-15 seconds (12 V)

I have a small excavator that, when fuel levels get low, the warning light flashes irregularly (due to movement of the machine) until it stays on as fuel level gets really low. It's very annoying and ...
5
votes
4answers
2k views

How does a logic gate behave with an input changing faster than its propagation delay?

I am attempting to create a simple logic circuit simulator. I am having a hard time figuring out how does a logic gate behave with an input changing faster than its propagation delay. When attempting ...
1
vote
1answer
294 views

FPGA input pin internal floating

I am now occouring a FPGA pin damage problem. One of my pin is hardware connected to a 1.8V signal that will be switched on/off occasionally, while the port is not connected to any other logic gate ...
0
votes
1answer
205 views

How to have 256 bit input for micro-controllers like Arduino?

I want to read 256 digital input, each of which is driven by a switch. I don't need to read state of all 256 switches more than 5 times a second (or may be even less). Multiple switches can be ON and ...
0
votes
1answer
582 views

Connecting Multiple Sensors

I have 4 pairs of "LED + LDR" sensor. I need to be able to switch each of them on/off independently and take reading from the LDRs. To connect all of them to the microcontroller board, I would need 4 ...
1
vote
1answer
74 views

Error in making pins input in PIC32

I am trying to make some pins act as input in PIC32MX795F512L. I am doing like this ...
0
votes
1answer
146 views

Arduino - Weird behavior reading speaker level input

I'm trying to detect when speaker starts playing audio, my speaker is connected with a 10uF 50v in series with the positive (red) cable coming out of my receiver, and negative to ground. Speaker (+) -...
1
vote
1answer
237 views

Power In does not Equal Power Out

I have the following setup: 480V, 200A service fed into PWM Drive, Drive output going to 1000kVA step up transformer (8.4 ratio) feeding a 2380V/53A 3phase induction motor. The motor is UNLOADED. ...
0
votes
2answers
420 views

Difference between an Analogue multiplexer vs ADC chip with lots of channels

Advantages and Disadvantages of Analogue Multiplexer vs a ADC chip. For having more analogue inputs on micro-controller. Thx
1
vote
1answer
2k views

How calculate the input offset current effect on measured voltage?

Here is the data-sheet: http://www.mccdaq.com/pdfs/manuals/PCI-DAS6034-35-36.pdf A data-acquisition board's differential amplifier measures a constant voltage across a resistor R1 shown in the Figure ...
-3
votes
1answer
117 views

Altera FPGA Pinout help [closed]

I recently bought an Altera FPGA Cyclone II board off of ebay, it says BAIXUN on the LCD display. It didnt come with any documentation. I'm trying to program the FPGA board but I have no idea what pin ...
0
votes
1answer
1k views

Amplifing guitar signal in order to connect it to ADC

I would like to connect an electric guitar to ADC (or MCU internal ADC input) in order to process signal digitally. I'm not sure right now which MCU or ADC I'm going to use, nevertheless I believe ...