Questions tagged [input]
Something put into a system or expended in its operation to achieve output or a result
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BJT Input AC Signal Amplitude
This question is referring to npn BJT CE:
If we look at base voltage vs. collector current plot we can see that at approximately 0.7V on base to emitter junction, the BJT starts rapidly conducting.
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12V input on microcontroller pin
I'm trying to count pulses/sec. on a microcontroller pin in the ~5 to 100Hz range. The µC can operate at 5V input, so I have to get the voltage level down safely.
A simple resistor comes to mind, yet ...
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What is the use for non-inverting input resistance in a negative feedback opamp?
Here in the Figure R5=50K.
This resistor value is not in the equations to obtain output voltage, and in many tutorials non-inverting input is directly grounded without a resistor. What might be the ...
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Multiplexing Inputs on a microcontroller
I have a 4 way DIL switch that I use to provide input to a microcontroller, and I need to free up a port to use for something else.
Is there a way to multiplex 4 inputs into 3 microcontroller ports? ...
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Input voltage range of opamps
I understand that, for an ideal opamp, Vo is bounded by Vee and Vcc (i.e.; Vee < Vo < Vcc).
But, what about the input voltage range? What is the allowed input voltage range in which opamp works ...
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PIC - How to skirt around low maximum ADC input impedance?
Reading a 9V battery on a PIC is nothing new. The most simple and straightforward way is with a voltage divider. I'd like to keep the divider resistances cranked up into the hundreds of kohms so I'm ...
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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:...
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Understading negative feedback [duplicate]
There is a question here about something similar, but it's asking about the internals of an op-amp. I'm having trouble understanding the function and use despite several hours of YouTube tutorials.
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5v output to 3.3v?
I have a microcontroller and a Raspberry Pi, both running off of the same 5v supply, in parallel. The microcontroller has 4 5v output pins and the other is a Raspberry Pi, that can only accept inputs ...
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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 ...
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How is this 5-24V input circuit working?
Since I require some kind of wide range input (going to a microcontroller) for a new project, I looked through some designs that are already in use (or were considered at some point) for other ...
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How to implement a "rotary switch" like in audio equipment?
for my current project I'm planning to use an input "device" like this in the photo (don't know its real name):
It is used in a lot of musical instruments and it is like a potentiometer that can be ...
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What's mean these microcontroller pin input/output modes?
I bought an stm32f103ret6. When I saw the reference manual, I saw that it has several I/O modes.
For input: floating, pull-up, pull-down
For output: analog, open-drain, push-pull
I have already ...
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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 ...
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Digital Input Clamp Circuit Protection
To be able to connect some peripheral to digital input, I'm designing the circuit protection to avoid any possible failure due to over/under-voltage issue. So, I will add a clamp protection circuit.
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Can an opto-isolated input be analog?
Title says it all: can an opto-isolated input be analog or are they intrinsically digital?
Why: I am looking to purchase a relay control board and am deciding between a few options.
Here is my ...
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MCU Input Protection
I am working on a simple protection circuit for an I/O pin on an MCU. The device will be 3v battery powered. The MCU's I/O pin has a voltage tolerance of (GND - .6V) to (Vdd + .6V).
Pull-to-ground ...
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Is there a way to measure the Phase Shift between the input and the output voltages related by the equation: \$V_o = V_i(a+jb).\$? [closed]
Say \$V_i\$ is an input voltage, and the output voltage is given by \$V_o = V_i(a+jb).\$ Is there a way to measure the Phase Shift between these input and output voltages?
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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 ...
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What are the mechanisms at work in a pull-up or pull-down resistor circuits with a push-buttons and a GPIO?
I have a question regarding the GPIO (from a Arduino board for example). How does it work exactly when you use it as an input pin? What are the mechanisms at work when you use it in a pull-up and pull-...
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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 ...
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Add a passive hardware token using a 3.5mm jack
I have a box that I made for my niece, which allows her to exchange voice messages with me. It is powered by a Raspberry Pi and features two buttons, a LED, a microphone and a speaker.
Now, for ...
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What kind of diode to use with ADC inputs
I am looking for diodes to protect my ADC from over voltage conditions. From what I have researched so far, I know that I need schottky diodes hooked up from the input to the ground and the input to ...
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Can unconnected inputs make an IC get warm?
I am using an ATF16V8 PLD for some simple glue logic. While testing it on a prototyping board, I noticed that it gets warm to the touch almost immediately. I checked that no outputs were short ...
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Simplest possible I/O for Homebrew 8-bit CPU
I am working on designing an 8 bit cpu as a personal project for no real reason. I am using mostly 74HC series chips and am generally focusing on ease of programming over performance.
I am using ...
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Considerations when using internal pull-up/down resistors
I am working with STM32 micro-controllers. These micro-controllers have the option to set the input pin as pull up or pull down:
Earlier I used to give external pull up or pull down resistor wherever ...
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12 V input on 3.3 V GPIO, TVS pulled down or Schottky pull up?
I am building my own PLC that has to accept permanent inputs of up to 30 V DC into a STM32F with 3.3 V inputs.
The switched input will have to work with 8-30 V, but 90% of the time the ...
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Where Does VDD+0.3V Input Limit Come From on IC chips?
There are a variety of integrated circuits that specify that their input voltage can span a fairly wide (absolute maximum) range, e.g. -0.3V to 6.0V (ref, pdf page 4), and then have a "Input Voltage ...
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How to trigger a transistor from iphone's audio output jack?
I want to trigger a transistor using iPhone's audio output jack. My goal is to turn off an LED(which is fed by an external +5V battery) by sending an audio signal from iphone's output jack. At the ...
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Wide voltage range input regulation (24V - 3.3V)
TL; DR: I need a circuit capable of handling input voltages from 24V to 3.3V (with a 10mA/5mA maximum current) and delivering 3.3V to the microcontroller (ESP32) input.
Recently, I've been working ...
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Arduino Analog Input example clarification
First of all I'm total nub in electronics.
Recently I got an Arduino Nano. Now I'm trying to understand why there is no potentiometer nominal at http://arduino.cc/en/Tutorial/ReadAnalogVoltage ...
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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 ...
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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 ...
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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 ...
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Several Questions About Analog Input
I am new in the automation industry, and now I am focusing on learning how to wire correctly analog inputs in detail, since last time I tried I damaged the module input because of wrong wiring.
Here ...
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Keyboard USB transform
I want to press a key on my keyboard, for example "a" and a device should take the scan code of the button I pressed and transform it to something else: e.g. "b" or the scan code ...
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Help to build a circuit to trigger event only after input signal changes from "1" to "0"
I'd like to build a kind of logic as shown in the picture ,but I can't do it and I really appreciate if someone can help on that.
Basically what I'd like to achieve is that when the input signal ...
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Does there exist an IC that allows on-the-fly routing of signals?
Do there exist ICs with N input pins and N output pins which, either via EEPROM setting or via on-the-fly control by a microcontroller, allow one to route each of the N inputs to ANY of the N outputs?
...
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Measuring input current of opamp
I want to measure the current that goes into a noninverting opamp input. I've setup my experiment as follows:
I can't measure the voltage drop across the 10M (R1) resistor directly since my DMM has ...
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Input impedance of an op Amp
I noticed that the input impedance of an op Amp is extremely high. Why is that so?
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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 ...
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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 ...
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Input range for TPA311x
I'm reading through the datasheet of the TPA311x family.
I'm looking for the input range for pins INPR and INPL but I cannot find this information. I see the absolute maximum ratings, but it's not ...
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Is 3.5VDC going to damage an stm32 analog input?
I have a pressure transmitter sensor that is supplied with 5VDC and provides 0.5-3.5VDC analog value within a pressure range of 0-4bar. The system that I'll be using the sensor within, will almost ...
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How can I interface with these 24 V signals?
I have a few 24V inputs to my micro controller from Limit switches. I have conditioned the signals as shown. Pulled down, de-bounced and level converted.
I have some signals that are again 24V but ...
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Sallen Key topology input and output impedance
Ideal Operational amplifier
Zi=(R1+R2)||Zc2
Zo=0
741 Operational amplifier
Zi=(R1+R2)||Zc2
Zo=0 (at DC)
For the input impedance when using a 741 I am not sure if I should consider the Fairchild ...
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DC Op-Amp Output at an unexpected voltage?
For some reason Op-Amps are impossible for me. I'm experimenting with them a little bit. I have the following circuit...
simulate this circuit – Schematic created using CircuitLab
This is the ...
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dsPIC 30F6012A will not read RD9, appears to be software problem
I'm using a dsPIC 30F6012A. I have two PCBs with this chip, both displaying the same symptoms, implying it's not one-off damage. RD9 is definitely being driven to five volts, confirmed with a ...
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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 ...
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How not to waste power with digital inputs?
I am trying to make simple gates with n-MOSFETS, yet I'm not sure how to actually do physical gate inputs correctly.
At first, I tried this (a single-pole, single-throw switch from +5V to gate). ...
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