# 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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### I/O Resistance of common source MOSFET with source degeneration

Common Source MOSFET with source degenerations looks like this I am a bit confused about different input and output resistance statements (provided by different sources). Some of them say that ...
3k views

### Do I really need the open loop output impedance of an op amp?

There are several answers on the internet and here on how to calculate the output impedance of the opamp with a given feedback. My intention, though, is to find this value with an open loop ...
20k views

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: ...
511 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 ...
10k 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,...
950 views

### 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 ...
1k views

### Common drain JFET output resistance “problem”

The output resistance of small signal model for common drain JFET amplifier equals $$\frac{1}{g_\text{m}} || R_{\text{ds(on)}} \parallel R_\text{S}$$ and since  R_{\text{ds(on)}} =\frac{1}{g_\text{...
368 views

### Formula for BJT common emitter output characteristics curve

I collected experimental data of input and output characteristics of a BJT NPN in Common Emitter configuration. I need to find the right function to fit the Ic vs Vce, but I'm not finding it. I've ...
7k 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.)
970 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 ...
548 views

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. ...
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 ...
7k 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 ...
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 ...
21k 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 ...
3k views

### Inverter Output Filters

I am designing a H bridge converter which is supplied with a 400VDC bus. The switching frequency will be 20kHz I want fit an LC filter to the output so that a sinusoidal voltage is produced, the ...
841 views

### Pulldown resistor on MCU output?

I'm using an MCU to drive a set of SSRs, and whenever I reboot the MCU, the outputs that I have attached to the SSRs go high temporarily. I know that a pullup/pulldown resistor can keep a CMOS input ...
703 views

### Output of a D flipflop upon power up?

I guess the output state of a D-flipflop is unknown upon power up. But what are the chances that it is neither 0 nor 1 but an intermediate state such as VDD/2? The D-flipflop in this question has an ...
3k views

### arduino thermal anemometer

I've been trying to use my arduino as a thermal anemometer based on the excellent and tiny IST FS5 "thermal mass flow sensor" - there is more information and a datasheet here - http://uk.farnell.com/...
1k views

### JK flip flop random start outputs

I am working on a project for college and I have to implement a sort of alarm using only MUX's and JK flip flops and a bread board. The problem I encountered is that whenever I power the whole circuit ...
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? ...
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 ...
5k 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 ...
566 views

### Is the dynamic resistance ignored in this output impedance formula?

Does the following tutorial neglect the dynamic resistance across the base and the emitter in derivation of the output resistance:? It assumes Vbe constant and ignores the dynamic resistance? But ...
59 views

### Measuring Output Ripple Voltage

Please check the below waveform of my 5V output ripple of the buck converter. I am measuring the output ripple across the output capacitor of the converter. Why are these spikes coming while ...
234 views

### What is the meaning of output of an accelerometer

I know this question is not fully related to aviation, but I assume the people on this subsection will also have some idea. Suppose I have an accelerometer resting on a table(flat surface, horizontal)...
624 views

### 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 ...
322 views

### 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 ...
621 views

### What decides that an IC will be able to sink or source current?

Correct me if I am wrong but so far, I've learnt that some ICs can source current while some can only sink (open-collector) while others can do both. And it is decided by looking at the datasheet, Ioh ...
231 views

### finding output resistance of CB amplifier with ro

I have this CB amplifier circuit below This is the small signal equivalent circuit arranged to find the output resistance R_out with the r_o included Here is my analysis below to find the output ...
136 views

### When a datasheet specifies output current is it per pin or aggregated for all pins?

When a datasheet specifies something like output current, as with the 74FCT244 or for example, is this referring to the aggregated output current between all pins or the capacity of a single pin ? ...
2k views

### Calculating boost converter maximum current output

I built a simple boost converter from junk parts to step a 9V battery up to around 100V so I can tinker with some neon bulbs. (Schematic below.) I didn't have any inductors in my parts bin, so I ...
216 views

### Output impedance of a 4mA to 20mA current loop

I have the most basic of basicness circuit. The implementation is a XTR115UA IC with a 40ĀµA - 200ĀµA input (based on sensor voltage) which is amplified to the desired 4mA to 20mA current in the current ...
3k views

### Confusion with output impedance of non-inverting and inverting opamp circuit

I'm trying to understand why the output impedance of non-inverting and inverting opamp circuit is almost zero. I found the following text on the derivation: Ī² is the closed loop gain above. But I ...