Questions tagged [output]

A signal or power being generated by one system for consumption by another, or a connection for that purpose.

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11
votes
5answers
4k views

Hardware solution to fade LED on/off with digital output

I'd like to find a hardware-based solution to make LEDs fade from digital pins. i.e. instead of switching on/off, slowly fading (500ms) into/out of full brightness. I can't imagine a small capacitor ...
10
votes
4answers
7k views

Confused about IN/OUT architecture of z80 chip

I am reading the manual, and it's a bit complex. I can't understand the machine code encoding for the life of me, but that's not my main concern ... my main concern is the address/data buses. I do ...
10
votes
2answers
97k views

What is a “dry contact input”?

I'm a PC software guy, a newbie to electronics. Recently, I've got a project in which I need to source for a DAQ that can provide dry contact inputs to an interfacing digital output controller. The ...
9
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6answers
7k views

Simplest, cheapest, fast and minimum footprint current limiting circuit with low resistance in normal state

I have a digital output, driven by the high-side driver with nominal voltage of 24V DC. The load current normally is below 100 mA. The output is monitored, so I can switch it off quickly if I detect a ...
9
votes
2answers
21k views

What does mean a rail to rail output opAmp?

Context : have a very similar problem to the one exposed here, and in the best rated answer (by Olin Lathrop), he says we need a rail to rail output opamp. My question : What is rail to rail opamp ?...
9
votes
4answers
3k views

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? ...
9
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2answers
3k views

meaning of set low/set high

I often see those phrases in tutorials with microcontroller I/O. An example use is "set pin 3 high", or "set pin 5 low for 20 ms". I also recall reading several different definitions on what that ...
9
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3answers
21k views

Reading and understanding electrical specs on laptop AC adapters

My Dell laptop comes with an AC adapter with the following specs: 65 W Input AC: 100 - 240 V, ~1.5 A, 50 - 60 Hz Output DC: 19.5 V, 3.34 A My HP laptop: ...
9
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1answer
1k views

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 ...
8
votes
4answers
11k views

Pulldown resistor on output pin, how does output still work?

On a part I'm working with, it says that you can configure the part to operate in a particular mode by "strapping" a particular pin to ground. That is, it wants you to use a pulldown resistor to pull ...
8
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3answers
646 views

Easiest and cheapest way to get digital outputs from a computer to the real world

I need a number of digital outputs to connect my computer to the real world, however it seems that this job is not nearly as easy as I had hoped. I've looked into a number of different methods, ...
7
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1answer
1k views

With a uC, I can input analog voltage levels, how do I output them?

With a uC, I can input analog voltage levels, how do I output them? I have a simple Arduino Uno R3 I had picked up, which has a few of each pin types (analog input, digital output/pwm, serial) and ...
7
votes
2answers
8k views

What does pulldown resistor from Arduino's output pin to ground do? Is it necessary?

I came across the first picture below. But I am not able to find out how such arrangement is necessary or beneficial when you want to switch a load with an N channel MOSFET? Question number 1: Is ...
7
votes
1answer
464 views

Input and Output pin voltage specs on a datasheet

I'm a bit confused about input pin voltage tolerances and output pin voltage values of ICs. I would think that datasheets for ICs that involve signal inputs/outputs would list two values: The ...
7
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2answers
6k views

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 ...
6
votes
4answers
9k views

Why do they usually make comparators open collector?

I never see open collector opamps while I frequently see open collector comparators. What is reason for preferring open collector output in comparators? (Inside of LM193.)
6
votes
1answer
617 views

What's the name of this output connector of ac adaptor

What's the name of this output connector of ac adaptor : Thank you for your help
6
votes
3answers
2k views

What shift register ICs am I looking for?

I'm designing a project that requires far more I/O than a typical microcontroller offers. No problem, right, just use shift registers and stuff. Wait nope, why am I having problems? I'm planning on ...
6
votes
2answers
533 views

Clipping Class-AB Output

This assignment we have been given has been causing me major headaches. I feel like I'm finally close to getting this amp to work after hours of fiddling around, but now I've found the output is ...
6
votes
1answer
3k views

What to do with unused TTL and CMOS outputs?

Just about everything I've read on the Web, including on this site, say that unused TTL and CMOS outputs should be left floating. However, this TI article, Designing with Logic, states: Unused ...
6
votes
6answers
3k views

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 ...
6
votes
2answers
327 views

Understanding resistors on inputs/outputs of op amps

I was looking at the schematic for Dave Jones' uCurrent, and I can't seem to make sense of why there are 270 ohm resistors on the inputs and outputs of the op amps in his circuit. The resistance is ...
6
votes
2answers
1k views

Programmable current source

I need to build a programmable current source from a 8051 microcontroller. It needs an output current from 0 to 10mA maximun. How do i go about doing this? what circuits do i need to build? I was ...
6
votes
1answer
1k views

Fourier series of output voltage

I've been practicing some Fourier series questions and then verifying my answers by generating an equivalent graph on MATLAB and comparing it with the graph generated by PSpice in simulating the same ...
5
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3answers
18k views

How to read a push-pull output

I recently came across a sensor that had a "push-pull" output. I can't find anywhere how to read such an output: Is it some particular kind of analog output? I would want to read it with the ...
5
votes
4answers
7k views

Purpose and explanation of resistor near output of LM317, high-current, adjustable-regulator circuit

I'm trying to make a high-current, adjustable-voltage regulator using LM317 data sheets. Specifically, I am using the schematic below. So, what is the point of the resistor related to Note A? Is it ...
5
votes
2answers
652 views

Is there a way to find the transfer function from only your input and the steady state response?

I know that a transfer function has the general form of $$ G(S) = Y(S)/U(S) $$ where \$Y(S)\$ is the output and \$U(S)\$ is the input. However, if given the output \$u(t)\$ and the steady state ...
5
votes
2answers
2k views

Op amp rectifier : transfer function and output impedance

I'm working on an EE student project which uses a rectifier to keep the peak value of a sine wave. You can find a PSpice pic of the schematics below (Ve is the input (1kHz), Vs is the output). Op amp ...
5
votes
2answers
662 views

Simple LM386 Circuit RC Branch Question

Please take a moment to checkout at the LM386 circuit below. The circuit comes directly from the LM386 specifications document: My question revolves around the output branch consisting of the 0.05 ...
5
votes
3answers
7k views

Correct Way to Limit Op Amp Output Current

I'm planning to use an AD817 op amp in the output stage of my function generator (datasheet). I'm worried about how the part would stand up to a short, so I ran some simulations. The simulation below ...
5
votes
1answer
13k views

What is drive strength a measurement of?

In microcontrollers and the like that have programmable drive strengths for GPIOs, said drive strengths are defined in mA. For example you might have a choice of 2mA, 4mA, 6mA, 8mA, etc. My assumption,...
5
votes
2answers
657 views

Rail-to-rail oscillations in subtractor op amp circuit

simulate this circuit – Schematic created using CircuitLab Just bumped into a problem. When I am trying to make a voltage subtractor based on AD8055 op Amplifier, I get rail-to-rail ...
5
votes
3answers
3k views

Using Single Ended Output with Differential Input by Grounding one Input

I am making a frequency generator using the AD9833 (programmed from the PIC16F876). I wish to use a Programmable Gain Amplifier to adjust the signal level before being sent to a power amplifier (...
5
votes
2answers
2k views

5V Tolerance of 3.3V OUTPUT pin

Let's assume the following scenario: uC (@3.3V VDD) drives an I/O pin HIGH 3.3V (just to be clear, it's not an open-drain pin, so the p-channel mosfet of the output pin is actually driving the pin to ...
4
votes
1answer
3k views

Understanding this statement in ATmega328P's datasheet

While reading ATmega328P's datasheet, I came across the following statement. The Port X output buffers have symmetrical drive characteristics with both high sink and source capability. What does ...
4
votes
2answers
5k views

Configure a PIC pin for Input and Output

I am working on a project which uses a PIC24FJ64GA002 mcu. I am working on a bit-banged serial communication function that will use one wire to send data and then switch to receive mode to receive ...
4
votes
3answers
5k views

Using lots of slide potentiometer for computer control

I want to mount a bunch (say 16+) slide potentiometers in a long project box (or other housing that can sit on a desk) that I can use to interact with software on my computer, specifically lighting ...
4
votes
3answers
1k views

Can I replace watch quartz with DS3231 32 kHz output?

I'd like to know if it's possible to synchronize classical quartz clock by replacing inbuilt quartz crystal with DS3231's 32 kHz output. I need to synchronize my analog watch with RTC DS3231. Am I ...
4
votes
2answers
373 views

How do I translate voltages to user-supplied levels?

I'm working on an AVR/JTAG/whatever programmer. The programmer will interface with chips running at various voltage levels, ranging from 1.8V to 5V. The programmer runs at 3.3V. The programmer ...
4
votes
3answers
12k views

How to enable Output pin to high by default in Arduino Uno?

In Arduino Uno, I noticed that when I set a PIN to output, the default initial state is low. Is there a way to set the initial output state to high? The pinmode documentation supports only ...
4
votes
3answers
181 views

Recommendation for a USB digital simulator

It's becoming quite frequent to me having a new digital subsystem which I want to test in isolation before trying to make a prototype circuit. I've been using the digital analyzer by Saleae for inputs,...
4
votes
1answer
6k 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?
4
votes
3answers
7k views

Speaker level to line level

I want to reduce my amplifier output to line-level. I found this tutorial, Connecting speaker signals to line level inputs, which is compatible with 50 W output power. There is also mentioned ...
4
votes
2answers
237 views

Handling audio (from mic to headphones)

Right, I'm new to electronics, but this is what want to know: What do I need to take a mic input, and output it to some ear phones (standard jack, can be mono). I want to build a motorcycle intercom, ...
4
votes
1answer
759 views

Netduino to power 12V LED Strip

I'm a programmer by nature, but I thought I'd try dabbling in programming a micro controller. I've hooked up my voltage meter, and have figured out how to switch my output ports on/off, and they're ...
4
votes
1answer
372 views

PIC pins change state when DC motor connected

I'm new to PIC programming, and having trouble getting getting it control a DC motor. It's a PIC18F25K22, and a TI L293D driver. Power is suppliued by a 5V linear regulator connected to a desktop ...
4
votes
2answers
4k views

Is pinch off voltage of JFET constant?

The drain current is related to gate to source voltage by the following equation: \$I_d = I_{dss} (1 - \frac{V_{gs}}{V_p})^2\$ Now, with changing \$V_{gs}\$, I think \$V_p\$ also changes. I am ...
3
votes
3answers
24k views

Maximum op-amp output current

Im looking to drive an LED, but am not sure if i should use an op-amp or bjt configured as a switch. Is it possible for an op-amp to source roughly 10mA; the current needed to drive an LED in series ...
3
votes
2answers
151 views

Inverting opamp amplifier

The gain of an ideal opamp is considered infinite and Vout=K(V+ - V-). where V+ is the non-inverting input and V- is the inverting input. The output voltage in the case of an inverting opamp amplifier ...
3
votes
2answers
637 views

Building a midi project with Arduino + scrap components (optocoupler and diode)

Original title: 300V output Optocoupler in a 5V circuit I'm (new to this) trying to build a midi controller (in and out) with arduino and scrap. I guess I had several questions in one so I changed ...

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