Questions tagged [optoelectronics]

Components, circuits, or systems that convert between electrical and optical (light) energy.

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50 views

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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42 views

How to check input and output of this circuit?

I needed to test the OPT 202 ( it is basically a photodiode with on chip amplifier). From datasheet I understood that the output is proportional to input current based on wavelength. I have given ...
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1answer
31 views

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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1answer
62 views

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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45 views

Help using an FOD3182 OptoCoupler

So this is the Optocoupler I will be using: https://html.alldatasheet.com/html-pdf/505064/FAIRCHILD/FOD3182/978/2/FOD3182.html My question is with the schematic of the data-sheet. Using Ni-multisim I ...
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1answer
139 views

How can I test a TLP582 optocoupler?

Have few of these components (TLP582) and I need to design a test circuit to test its functionality. Datasheet of TLP582 I have no idea how to make a circuit for this. What should I be testing in an ...
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1answer
43 views

Driving a 14-pin with DFB laser using D2570H

For our project, we would like to use the D2570 DFB laser from Agere system since it has a built-in photodiode with a TEC sensor, thermistor and a bias-tee embedded in an 'all-in-one' package. However,...
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1answer
75 views

Circuit to replace a relay

I want to make a simple ladder circuit to control the on and off of a light bulb using 2 switches, but I am going to manipulate one of the switches by means of a microcontroller, and also I don't want ...
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1answer
45 views

Understanding peak repetitive surge current

I have moc3021 optocouplers. The data sheet says it has a peak repetitive surge current rating of 1 amp, 120 pps. I was hoping to use a microcontroller to control 24V .800A AC with this optocoupler. ...
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2answers
50 views

Best way to AND all connected inputs to one output

I have an CNC router with 7 x SN04-NPN sensors connected in parallel with one control board input. The problem is obvious, i got random false endstop triggers due leaking of SN04. I know i should have ...
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3answers
1k views

Position of current limiting resistor

I am designing a digital output circuit. I got confused about the position of the current limiting resistor of the transistor. I would like know where it should be. (After or before the pull up ...
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1answer
39 views

How to compare OLED and LCD brightness

I am trying to build a night clock projector, inspired by this project: https://microengineer.eu/2018/05/01/diy-night-clock-projector/ As I am more a computer scientist than an electrical engineer, I ...
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49 views

Ham Transceiver to computer Interface design question

I am building a Ham transceiver to computer interface, which has the RS232 port controlling the PTT on the radio. The circuit currently calls out for a 1.2K resistor in series with the RTS line and ...
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78 views

Photon lifetime in an optical cavity

Hi I have the following problem and data for an optical cavity. Length \$ L=100 \mu m\$ Reflectivity \$R=0.33\$ Refraction index \$n=3.6\$ Inner losses \$p_i=20 cm^{-1}\$ Now I have to determine the ...
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21 views

Getting the optical power of a UV-LED using a spectrometer data

if it is possible can you let me know the way to get the radiated power of a UV-LED using the output data from the "Ocean optics- Maya pro 2000" spectrometer, or the calculations needed to ...
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2answers
47 views

what is the reason behind DC level shift of the optoisolator ouput(collector of photo transistor) terminal?

i am using SFH-610A optoisolator to switch 1KHZ PWM signal. on input side of opto i am triggering from micro controller with series resistor 500 ohms. and on the output side i have pull-up of 3.3V ...
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1answer
49 views

Resistor between vcc and control signal in a rpi controlled relay board

I have been researching to design a rpi controlled relay board and I found these two schematics from two companies. Personally I trust the company in the image above but I am confused about R3 (10k) ...
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1answer
66 views

How to share a digital signal between circuits?

Please see this : The Task I'm trying to create a single module which can safely share a single digital signal. The idea is that each (identical) module can monitor the status of the signal, and can ...
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1answer
66 views

Please help me understand how this inductive proximity sensor works

I'm trying to build out an optocoupler circuit to connect a new proximity sensor to my 3D printer and want to understand how it behaves before implementing. It's a Printrbot Simple Metal, Printrboard ...
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3answers
136 views

A laser driver (MLD203P1) with an external Bias-Tee for modulation

As the title says, I would like to add an external Bias tee to modulate a high frequency signal into a laser diode, because the laser driver I have chosen does not have a built-in modulation circuit. ...
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1answer
80 views

Opto-isolation amplifier output is too off

(As a follow-up to an earlier question answered by the community - thanks!) So I've got the test circuit setup using the HCPL 7520 (datasheet) now and planning to use an Arduino Uno to measure the ...
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3answers
59 views

Opto-isolation amplifier giving no output

First of all, thanks to the community for having such helpful answers here - don't post very often but here's one I could really do some help with. I want to measure a voltage range of 0-100V DC in an ...
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What's the reason for keeping a base line in optocoupler? [duplicate]

Image Source: https://www.vishay.com/docs/83725/4n25.pdf The pin no 6 of the optocoupler IC is connected to the base of the NPN transistor. Should I keep it open? Or grounded? Does it anything to do ...
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4answers
143 views

Laser scanning: Why are things like deflection and mirrors used instead of just a mount and servo?

In the Wikipedia article for laser scanning, it is said that laser scanning is the controlled deflection of laser beams, visible or invisible. It then lists some of the technologies used, such as ...
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1answer
54 views

Photo-multiplier Tube Pin Configuration

Pin configuration of a photo-multiplier tube (PMT) is presented in its manual as can be seen in the attached image. All dynodes have been related to specified pins (numbered circles in the image) ...
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2answers
36 views

Biasing network for phototubes and photomultipliers

I have some doubts about typical biasing network for vacuum phototubes and photomultipliers. Precisely, let's start by a simple photocathode. I have seen some biasing network like this one: In this ...
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1answer
76 views

Charge transfer in CCD

I have a basic doubt about charge transfer between pixels of a CCD. Let's consider this animation (picture taken from wikipedia): A precise time sequence of applied voltages between gates and bulk ...
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2answers
188 views

Photodiode Equivalent Circuit

I have some problems on understanding this equivalent circuit for a photodiode (picture taken from this article): The author states that: The equivalent circuit for a photodiode is shown in Fig. 1, ...
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3answers
1k views

Choosing series resistor for Optocoupler LED

How do you choose the series resistor value for the LED side of an optocoupler. My application uses this opto to interface a button that is about 25meters(50 meter wire roundtrip) away from the device....
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55 views

Why are thin-film surface-mount resistors particularly suitable for use in cryogenic environments/conditions?

I am currently studying The Art of Electronics, third edition, by Horowitz and Hill. Appendix C.4 Resistor types says the following: The usual choices for general-purpose use are metal-film (axial-...
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1answer
130 views

Is it possible to model a PIN InGasAS photodiode in a SPICE simulator?

I want to know if it is possible to model a InGasAs panchromatic PIN photodiode, in accord with datasheet, in simulator SPICE MicroCAP 12. Because the supplier doesn't provide a SPICE model. And if it ...
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1answer
71 views

DC Solid State Relay Common Ground

I have an application which would involve having data lines connected to a microcontroller which would signal at lvttl (3.3v) levels and also take in 24v for a resistive load (~600mA). I have ...
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1answer
36 views

Raspberry pi to sense voltages 12 to 24, what buffer is good?

Hello I’m looking to use my raspberry pi in an automotive application where it will be used to detect when the vehicles ignition is activated and de activated. I would like the system to be 24 volt ...
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56 views

Photodiode, analog electronic

I am a beginner PSPICE, in simulation electrical and electronics circuits. I want to simulate a schematic with the program Micro-CAP 12. I want to look for some graphics from a photodiode PIN which ...
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2answers
103 views

Optocoupler Reference

I want to use in my project an isolated optocoupler like this one to switch an IGBT. In the following schematic, taken from this Vishay application note there's a "floating supply" in Vcc1 as you can ...
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3answers
109 views

Are optocouplers enough of a protection to sensitive electronics

There are certain lines in my car which I want to detect when hot. My initial thought was to hook a voltage divider to drop from 12v (or ~14 rather) to 3.3 and feed it to my pi but I soon realized ...
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3answers
179 views

Ultra-narrow beam spread LASER diode

I want to build an optical position tracking system based on PSDs (Position-sensitive detectors). I searched online and found this PSD which has a sensitive area of 12 mm*12 mm. My goal is to allow a ...
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1answer
137 views

What is this black, marking-less, 6-pin surface mount device?

Below you can see the device I'm trying to identify: It is mounted underneath the expression pedal in one of these: Basically, below the pedal there is a little plunger which gets closer or farther ...
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1answer
107 views

Can I drive an optocoupler input with just 0.5mA (500 microA)?

Im trying to interface a keypad button in a device with a MCU, and they need to be in different circuits, with no shared GND. This keypad button has 5V DC when not pressed, and 0V when pressed. I ...
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1answer
47 views

IR diode radiation spot area

How large is an IR diode radiation spot area? I put some IR diodes (receiver and transmitter) in front of each other. I want each transmitter IR diode to only radiate on its reciever and not effect ...
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1answer
48 views

Gate-Souce resistors needed?

I completed an IR emitter circuit with two selectable power settings. It's working on the breadboard and I'm asking if I need the gate-source resistors for stability? As the circuit is battery powered ...
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1answer
67 views

Electroluminescent wire and EMC

I have been thinking about using EL wire in our house as a night light but I am concerned about electromagnetic compatibility and possible adverse effects on the inhabitants (we). You can see these ...
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1answer
62 views

Photodiode not working in reverse bias

I'm using a photodiode module, model: coaxial InGaAs, Gtel. I set it in reverse bias with 5V and tested it with a laser but it doesn't give any output voltage. Unfortunately I don't know the laser ...
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1answer
414 views

Optocoupler/isolater circuit for 24VDC sense that transfers switch status to 3.3VDC microcontroller

hope everyone is having a good couple weeks before Christmas, I was given this question for an assignment How would you use an opto-isolator to sense a switch status in a 24VDC machine control ...
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1answer
348 views

Is this optocoupler driving relay circuit reliable and works great?

This is the circuit that I have, the optocoupler is an EL817 and the transistor is a BC817, the 24V relay is an Omron g2r_1_e, a 24V coil relay. But when the optocoupler input is floating (not ...
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1answer
64 views

How do I model the optical coupling between two optoelectronic devices?

I'm building a circuit composed by two parts that are electrically isolating. One part has a LED (model: SIR333) and a phototransistor (model: SFH309FA). I basically have to model the optical coupling ...
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2answers
104 views

Simple switch with TLP222A

Electronic newbie here. I'm trying to use a TLP222A as a remote switch for a small signal (3V and about 150-200mA at most). It's super simple, but I can't understand why the following happens: I'm ...
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2answers
96 views

Are mechanical relay signal pins isolated from the output?

I am going to use a magnetic mechanical relay to switch 240v AC. I am using MPC250D6Z05APT, in its specification it did not say that the 5V signal is isolated from its output upon failure of the ...
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1answer
58 views

Optocoupler min collector-emitter voltage

I'm looking for an optocoupler but looks like I don't undersant their parameters well. What is "Optocoupler min collector-emitter voltage"? For example, I found optocouplers like this but in the ...
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1answer
62 views

How does one match irradiance to Luminous Intensity in Candela of source?

A light source has an Irradiance of about 1.6 W/m²/nm at wavelenght 385nm and an LED: Peak Wavelength 385nm Viewing Angle 30 ° Luminous Intensity 80 mcd If this light source shines on a ...

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