# Questions tagged [input]

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

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17k views

### 3 input XNOR gate operation

For 3 input XOR gate and XNOR gate, by solving the equations I got the result as in the picture. So according to the solution the outputs of the 3 input XOR and XNOR gates are same. This solution ...
3k views

### Why do we need bulky filters at the input stage of SMPS designs?

I usually see costly and large filters at the input stage of switch mode power supplies. Isn't the AC signal already filtered by the large capacitor (the 100$\mu$F one in this example) after the ...
146 views

### What is meaning of active low input in combinational logic circuits?

I am currently doing self study on combinational logic circuits. I encountered few terms like active low output, active low input. I understood what active low output means (putting not gates at ...
421 views

### Define input current of Op-Amp

I haven't done and studies in Op-Amp category yet but I watched a (trusted) video on Youtube and one thing is not quite logical as the next sentence: "No current flows in or out of the inputs of ...
4k views

### Input and output resistance of an opamp circuit

Recently we have been working with opamps in the lab and I never can understand how to determin the output and input impedance of a circuit with op-amps (not the input and output inpedance of the ...
1k views

### Verilog data input

Hello I am relatively new to verilog and need help on part of a project am working on. I need someone to guide me as to how you read data from an analog device. I bought an analog temperature sensor ...
1k views

### Input clock signal with noise

I design a frequency divider in FPGA. It is nothing more than the D flip-flop, which use the inverted output as input. Then on the output of D flip-flop is signal with half-frequency of input CLK ...
174 views

### PWM controlled Input Voltage/Current regulated Converter (for solar panel)

(newbie question) Briefly: In a converter (let's say DC-DC), I want to dictate a voltage to the output of solar panel, on the fly. As I look around online, for example in some IEEE papers, Buck or ...
300 views

### What is the difference between digital input with low bias and digital input with high bias?

I have 3 inputs. Input #1 is low bias. I can hook up a 12V positive to input 1 and it will change it's state to 1 (or input is ON). Inputs #2 and #3 are high bias. Connecting a 12VDC to either of ...
806 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 ...
6k views

### What kind of metal are the legs of resistors made from?

Can anyone tell me what kind of metal is used in electronics to make wires going in/out to the elements? Can longer of this metal wire be found anywhere? Actually I am looking for sth like copper wire ...
687 views

### How to limit negative voltage on uC input pin

I'm trying to design a pulse induction metal detector to increase my EE skills a little bit. I started to sketch out the transmitting stage, which is just a MOSFET that switches current through a ...
2k views

### Connect different devices (Ground/Voltage mismatch)

To begin with, I realize that voltage is relative but I do not understand how to get a common ground so that everything is relatively correct to go in and out of the various chips. The picture ...
535 views

### Arduino LilyPad Input Voltages Below the Input Voltage in Specs

The LilyPad spec page says: Input Voltage 2.7-5.5 V I understand that an input voltage greater than 5.5 V would damage the device, but what if it's below 2.7 V?...
331 views

### Op Amp input protection

I was looking for an Op Amp input protection circuit and the most common I found looks like this. When the voltage at Input Signal goes above/below Op-Amp's supply ...
2k views

### Voltage detection / Universal uC Input => CLD, PTC

I'm currently developing a open-source "Home-PLC" for home automation. Every thing runs fine so far and I have a module with fixed voltage AC inputs and outputs. In the next step I want the build '...
3k views

Hi I am facing some problem with Reading the input from a PIC18f4550 , for a simple arrangement where when a switch on (switch = 1), few led should glow., and on releasing the switch the led should go ...
4k views

### Digital input ports of the dsPIC30F4011/4013 not working on the dsPICDEM 2 Development Board

I have a Microchip dsPICDEM 2 Development Board with two microcontrollers on it: a dsPIC30F4011 (Motor Control Family) and a dsPIC30F4013 (General Purpose Family). I'm programming in C using the MPLAB ...
2k views

### Measuring 230V from Raspberry Pi

I have a problem: We use some Raspberry Pi to manage some contactor with a simple relay. This relay can manage one or more three-phase switches, so basically it is linked at least to three contactors. ...
960 views

### Finding the input resistance of an oscilloscope

I'm having a little trouble understanding how to do this problem. So an oscilloscope measures a battery voltage of 1.5V, and when a 1M(ohm) resistor is put in series, the oscilloscope only measures 0....
7k views

### Recommended voltage/current for dry contact input?

What would be a reasonable value for voltage and max current to used in conjunction with a remote dry contact output so that it can return to my MCU (through isolator)? I plan on using this input for ...
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 ...
1k views

### Invert PWM input with NOT gate

What practical advantages could there be in using a logic NOT gate IC (e. g. schmit trigger hex inverters) when compared to a simple NMOS + pull-up resistor inverter? I want to invert the PWM output ...
8k views

### difference between dry contact mode output and open collector output

We have a device which can work with dry contact input and a device which gives open collector output. Will it inter-operate? Is there any difference between dry contact mode output and open ...
351 views

I have a hall sensor throttle which outputs a signal that scales between 0.8 and 3.6V. The problem is that when I connect it to an Arduino MEGA2560 analog input pin, the voltage never goes over 2.3V, ...
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 ...
224 views

### Utility of two pins requiring same voltage

I have a LED backlight driver, which has input pin assignment as: Pin Function 1,2 12V Input 3 Brightness control PWM : 100Hz~20KHz DC : 0.5V~2.5V 4,6 GND ...
167 views

### How can I get this to not read an arduino digital input?

I have been working on this for a while. It is a small part of a much bigger code. I have a digital input pin connected to a on/off switch and another input pin connected to a momentary push button. ...
365 views

### Can you use a stepper motor as input?

I'm not too versed in EE so I apologize for my duncitude - My thought is that you can precisely control a stepper motor, but can you inversely get precise readings out of a stepper motor? For ...
182 views

### Handling large number of inputs in PIC microcontroller

I am interfacing PIC32 MCU with 24 inputs and UART. When any inputs comes, this data is transferred to PC via uart. I am using multiple if condition like ...
2k views

### Arduino all input pins same value

Here's the situation: I have an Arduino mega 2560 and I'm trying to analogRead from 2 different pins. code: ...
2k views

### Bipolar Op Amp w/ Near Zero Offset?

My understanding is that if source resistance is low, a bipolar op amp has 10dB less noise than a JFET. I prefer the JFET op amps because the input offset is so low that you can eliminate coupling ...
305 views

### Digital Circuit question - sensing input across power rails using a micro

In the Circuit shown below, I am trying to achieve the following (I know my circuit is not correct, it is an attempt). Problem: WHen INPUT_N = 0V, the input to the microcontroller does not go low. ...
533 views

### Input impedance

I'm trying to figure out what the input impedance of the ADF4113 is. Looking a figure 15, I'm not sure how to read that. In my setup input is on RFinA and RFinB if connected to GND via a 100pF ...
1k views

### Balancing Unbalanced Audio Inputs

I'm wanting to nicely balance some unbalanced inputs to a power amp for good CMRR, and because I'm feeling too lazy to start trying to closely match pairs of resistors, I'm looking at using a hi-fi ...
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 ...
512 views

### How to work out or calculate this circuit?

I'm not an engineer, I understand a lot but I fail to understand how it works and how to calculate this for a 24vdc input:
1k views

### How do I get a relay to recognize when a TRRS jack is plugged into my iphone?

I'm working on a project where I would like to put an aux input in my car. I was thinking of hooking up my CD changer output wires to a relay and then hook up the aux wires to the other part of the ...
329 views

### AT32UC3C Negative ADC Input Voltage

The AT32UC3C ADC can be set up using either internal or external references as seen in Table 36-8. For any type of voltage reference used, the datasheet suggests that the ADC is capable of converting ...
361 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, ...
490 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 ...
5k views

### Latched outputs on 8255A

I am studying about the 8255A PPI. In Mode 0 of it, it says that the outputs are latched and inputs are not latched. What exactly does it mean?
347 views

### Single input for consecutive state transitions in an FSM: preventing fall-through

Consider the following state diagram where the inputs are c and v. The system is also receiving a high frequency clock ...
115 views

### Enable connected to unpowered regulator on another board

I have an ARM board which uses a VIO of 1.8V and requires that no i/o line be driven before it is fully powered up. It signals this readiness by asserting its "SYSEN" line. My design has SYSEN from ...
2k views

### What is the use of dual differential amplifiers in audio applications?

Why do audio amplifiers use dual differential pairs sometimes? Is there a mathematical justification and not just "the joy of symmetry"? Any hints, especially with some math would be of great help. ...
2k views

### Atmel Xmega ADC input voltage range - Can the ADC be damaged by exceeding it's reference voltage, if the input is still less then VCC?

I've been working with Atmels ATxmega parts a lot recently, and there is one question I still have that I have not been able to find a answer to, even after scouring the datasheets. Basically, The ...
637 views

### CD40106 output voltage

I'm testing some CD40106BE from Texas Instrument, CMOS Hex Schmitt Trigger (Datasheet Here). Vdd = 5V (Pin14) Vss = GND (Pin7) Vin = 5V I measured a Vout = 3.8V on every IC I tested, with a Led on ...
1k views

### Vbe vs Ic characteristics of NPN transistor at different Vce in active region

Below is an NPN transistor characteristics for Vbe versus Ic at different Vcb or Vce: It seems like in the active region, Vbe vs Ic curves gets steeper with an increasing Vce. The following ...