Questions tagged [optoelectronics]
Components, circuits, or systems that convert between electrical and optical (light) energy.
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Does Optocoupler with Low Collector Current Work?
I am working on a schematic which was not started by myself. From the datasheet of LTV-816S-TA1-D, The CTR is from 300% to 600% and I set the forward current I_f to 5mA.
However I notice that, given ...
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Current measurement from constant current source
I have a constant current circuit using an op amp circuit. I am implementing a current of 21 mA to drive a laser.
Spec of laser: https://www.thorlabs.com/thorproduct.cfm?partnumber=L650P007
I would ...
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What should be the output circuit of ADM01 (Bought from Thorlabs) used in QEPAS setup to give signal?
I am working on building a QEPAS setup. I am using HHL-513 as laser and ADM01 from Thorlabs. Inside the ADM01, there is a QTF(Quartz Tuning Fork). Basically, for the setup to work, what we have to do ...
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Simulating an equivalent circuit model of a laser in LTspice, how does it solve this circuit?
I want to know how LTspice solves this circuit as there are node voltage (vj) dependent current sources (Ist and Isp) present in this circuit. Also, I had an unknown parameter, Ne, whose value I ...
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Zero crossing detector - MCU interrupt is delayed
I'm trying to catch zero crossing (using below circuit) when it exactly happened. Rising and falling edge intervals are not equal and they need 0.3-0.7 ms to reach corresponding logic level. Let say ...
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Connecting 6 push buttons with ESP32 with 1 common pin
Hey all I have 6 buttons that have the following voltage:
I want to hook up a 4N25 to each one of these so I can use the ESP32 as a "virtual push" to each of these buttons. When the button ...
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How does a 4 pin RGB connector work without ground?
The question is in title. Why there is no ground pin on the 12V RGB header? The 5V ARG header which uses only 3 pins has a ground.
How does it work without a ground?
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How to understand output of TSOP4838 IR receiver?
I am testing the output of the following basic IR transmitter/receiver circuits and not getting the result I thought I would.
simulate this circuit – Schematic created using CircuitLab
I have ...
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Is it possible to plot an equation in LTspice? I am supposed to plot an equation like this v(t)=d/dt(ln(pout(t)) + kPout(t)
In the equation mentioned above, Pout is the voltage at some output node in my schematic. Is it possible to plot the above equation? how to plot v versus time?
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Quad IR pickup output inconsistencies
I've designed a quad IR pickup for a stringed instrument. The pickup works well, except that the output level of each string is different. Some strings (particularly the left two channels in the ...
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Characterizing a PIN photodiode's 3 dB bandwidth
I'm currently attempting to characterize a PIN photodiode's 3 dB bandwidth. The photodiode input is a laser source that is being modulated by an ESA RF output that performs a frequency sweep from 0-1....
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Safety regulations (USA) for high-power LED brightness (e.g. 1+ W)
For a "mostly" shielded sequence of 1 W where a user will see light bleed through small gaps in a device and (for argument's sake) might see a direct reflection of one of these 1 W LEDs (a ...
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What is equilibrium carrier concentration in a semiconductor? Is it material specific? How to calculate it?
Is equilibrium carrier concentration dependent on doping density? If it is, then how to know how much the doping density should be for a particular semiconductor device?
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I am simulating an equivalent model of a laser in LTspice shown below. I am supposed to plot the power at node Pout versus the input current
The issue is I am not able to plot the power without adding the load resistor which is not specified in the equivalent circuit.
Is there any other way to plot the power? If not, then what value of ...
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What makes an InGaAs detector more sensitive to infrared light?
What makes an InGaAs detector more sensitive to infrared light than visible light, considering that visible light has a higher photon energy?
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Implementing direct digital synthesis in STM32 microcontroller
I am working on a project that requires phase locking (digitally) of an output signal from a sensor to the reference signal which needs to be done on STM32 microcontroller. I am new to this area, and ...
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Any theoretical reference for empirical equation for estimating oxygen saturation (% SpO2 = 110 - 25*R)? [closed]
The empirical equation used to estimate % SpO2 is based on the observation that the ratio of the red and infrared light absorbed by arterial blood (represented by R in the equation) varies linearly ...
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Difficulties with multiplexing PPG signal in pulse oximeter
I've designed pulse oximeter circuit. When one LED lights continuously, I got perfect PPG (Photoplethysmogram) signal.
Then I measure PPG while blinking LEDS, like that:
I got stuck. There is no ...
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Detection of mechanical relay sticking
I'm exploring new methods to find if relay contacts have been stuck together without using auxiliary contacts of the relay. while searching I find out this block circuit:
at this Toshiba page
as far ...
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Low pass filter (?) in Thorlabs PDs
What is the purpose of this circuit in all Thorlabs PDs? It looks like a second order low pass filter to me, but shouldn't it be two resistors in that case?
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How to drive this specific laser
I've done just a circuit to drive an old laser and it was like this one:
I was wondering if it could be suitable for driving the laser whose datasheet is reported below.
I have these requirements:
...
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Measuring low lux with ambient photodiode
For my application, I need to detect two light levels: pitch black (close to 0 lux) and a low ambient light level of about 0.1 lux (or higher). It seemed like the BH1680FVC ambient light sensor was a ...
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How to choose a phototransistor or photodiode?
I've found a photoresistor (yes, resistor, probably 30 years
old) in my scrap box, attached it to an ATtiny as ambient light
sensor, with a 100kΩ resistor as voltage divider towards +5V.
On power on, ...
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BT136 TRIAC waveform
I am using a TRIAC to switch an AC signal
(a typical example is shown in question Triac Switch Circuit using MOC3021 and BT136).
When a BT136 TRIAC is used to switch a pure sinewave signal, I want to ...
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How can we explain this strange phenomenon with an optocoupler switching?
Two optocouplers are connected according to the circuit below. The input voltage across the first optocoupler is a true square wave (3.3 V amplitude). The first optocoupler is an open collector output ...
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DVD burner laser identification
I just disassembled the DVD writer from a laptop and scavenged some parts. Around where the laser and mirrors and opto stuff are packed together, I extracted these parts.
Which one is the laser diode ...
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What does the VCC pin do in this Optocoupler?
I have this optocoupler, and I am trying to figure out how it works.
What is the VCC pin supposed to do? How does it supply current to the gate pin of the transistor?
https://www.digikey.com/en/...
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Using a LED as a debug serial port
I want to add a debug serial output port to a device that's sealed in epoxy. I plan to use one of three existing 3mm LEDs (red 617nm, green 568nm, or yellow 588nm), ±30° angle, that emerge from the ...
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If composite transparent materials thermal and electrical conductivity can be adjusted t what would be benefit?
Will it be provided less thermal and electrical gradient to support less dissipative system development for opto-electronics and related technologies?
For thermoelectric design how it cold be ...
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Is it possible to control the frequency of light?
I mean, controlling directly in the source, not filtering the light or arranging density of the medium. For example, brightness can be controlled by current or voltage directly. However, when I came ...
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Can anyone identify this chip which I think to be an optocoupler?
I'm trying to troubleshoot a Renishaw H-2000-5062-07-A optical receiver for a tool piece used in a milling machine. It has several of these 8-SOIC(?) parts and I very much suspect that they are ...
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How to track, measure, manipulate and/or synchronize the phases of trapped ion qubits [closed]
I am working on a simulation of the Honeywell trapped ion quantum computer. The papers say that it tracks the phases of the qubits using "opto-electronics" but it doesn't give any detail.
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Looking for 5mm discrete multi color LED [closed]
I want to make an electronic version of the Master Mind game as a hobby project. The challenge at the moment is to find right type of LEDs for the job. Below you ...
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Why are low band gap semiconductors (like silicon) not ideal for most solar cells? Are their atoms ionized by higher-energy photons?
Most sources on the web say that 1.3 eV or 1.4 eV is 'ideal' for most solar cells...
What happens to lower-gap, gapless or overlap materials (conductors)? Are they ionized, rather than sending their ...
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How to know which opto-coupler is suitable for high current application?
I would like a suitable opto-coupler to use as isolation from a 12V and around 30A current and another for 5V and around 30A. Are there any good opto-couplers for those ratings?
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SSR for Attiny85 using Optocoupler and Triac
Looking for some advice, I am trying to create an onboard SSR to control the switching of a 120VAC load (heater/lighting), with an operating power of around 1500W max. I chose the following parts and ...
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How to know the minimum LED current of an optocoupler?
I am going to need to use an optocoupler to isolate two circuits in two situations. In both situations, a MCU GPIO will be driving the LED of the optocoupler to send a signal on the other end.
I am ...
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What is wrong/missing from the process subsystem? [closed]
My teacher told me to reconsider the process subsystem but I'm not sure what is really missing from it.
background story: when a guy is standing on the porch, the LED lights up
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What is the purpose of using an analog optocoupler?
What's the purpose of using an analog optocoupler in this circuit? Why not a digital one?
An industrial battery charger. Normal operating voltage to monitor ranges from 120 V (Battery low) to 180 V (...
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Amplifying a small signal from a phototransistor
I am building an amplifier for a phototransistor. It works well under normal lighting conditions.
In my application, the light is very dim and barely produce any readable output.
I tried to increase ...
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What is this component ? Negative tiny LCD glass?
I disassembled a ceiling projector clock to find out how it achieves its projection. I found a very small screen (or glass, see image) backlit by an LED.
To build some projecting stuff, I would like ...
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How do I simulate a short/open circuit in LTSpice?
I am trying to simulate open/short conditions for testing an optoisolator circuit I'm building.
Essentially, I need to simulate SHORT and OPEN in order to verify that what I'm designing will output ...
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Opto-Isolator FODM 8071 switching noise at output Issue
I am working with Logic Gate Output Optocoupler. I have tried removing 15pF capacitor but it didn't made any difference.
On output port it is generating noise
Any help would be appreciated..!
Thanks ...
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How does this optocoupled smoke sensor circuit work? [closed]
This is an optocoupler module consisting of an infrared LED coupled to a phototransistor as smoke sensor.
I got this circuit from this site.
According to T.K. Hareendran says:
For optimum ...
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Is it possible to generate light with an antenna?
An antenna (e.g. a dipole) is able to radiate at a certain frequency thanks to the EM field generated by a current provided by a signal generator at such a frequency.
So, for instance:
Voltage source ...
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Why do we have a limited bandwidth in electronics?
I've been looking around a bit on optical communications and it is said that the main advantage in using optical communications, namely optical fibers, lies in the gigantic bandwidth available, when ...
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AQW610EAH-PhotoMos Relay
Can we apply voltage across 1 and 2 pins to control normally closed (N.C) and to pins 3 and 4 for normally open (N.O) at the same time in AQW610EAH ICs (pin diagram of that IC above)? Or only one N.C ...
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Can I use 1 optocoupler to drive 4 MOSFETs?
I've this circuit and works correctly, now I need to control 4 MOSFET instead of 2, is the second schematic correctly?
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Adjusting Voltage regulator with PWMed optocoupler
I have LD1084V adjustable voltage regulator powering servo and want to control its output from MCU. Optocoupler should behave as variable resistor so my thinking was :
I am mainly concerned with gray ...
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Opto-isolator/ optocoupler for electric isolation in IC design
I came across while reading the opto-isolator technique used for electric isolation in embedded systems/ Integrated Circuits design that " Opto-isolator is not recommended for electric isolation ...
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