# 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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11k views

### 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 ...
4k 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 ...
2k 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{...
516 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 ...
661 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 ...
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,...
21k 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: ...
612 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. ...
1k 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 ...
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.)
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 ...
5k 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: β is the closed loop gain above. But I ...
322 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 ...
1k views

### Output impedance seen by the load in this emitter follower

I'm trying to understand what the concept of "output impedance" relates in a simple buffer such as an emitter follower conceptually without digging in formulas. Imagine the Rload is about to be ...
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 ...
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 ?...
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 ...
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 ...
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 ...
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 ...
1k 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 ...
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/...
801 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 ...
2k 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 ...
76 views

### 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 ...
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 ...
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 ...
711 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 ...
453 views

### Determining Impedances of an Op-Amp Circuit

I'm trying to review some old concepts, and thus far, there was one that I couldn't really understand: impedance of circuits involving op-amps. Assuming an ideal op-amp, it has infinite input ...
359 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)...
10k views

### How much voltage does a green LED need to be supplied? Will it handle 5V?

I’m supplying 9v through a 5v regulator. This regulator powers five IC quad gates. This is all for a 4 bit ripple carry adder. With that aside, could I just power the LEDs (which will visualize the ...
393 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 ...
107 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 ...
792 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 ...
981 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 ...
3k 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 ...
156 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 ? ...
286 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 40µA - 200µA input (based on sensor voltage) which is amplified to the desired 4mA to 20mA current in the current ...
1k views

### How to differ output & input resistance of small-signal model BJT?

I understand how input and output resistance of small-signal model for bipolar transistor is defined and how draw one. What I don't understand quite yet is how actually input and output resistance of ...