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Questions tagged [optoelectronics]

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

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1answer
48 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
48 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
53 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
74 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
58 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
43 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
85 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
30 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
26 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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0answers
13 views

Single-Sided & Double-Sided Heterojunction

I am studying electronics engineering. I am troubled with finding the actual meaning and application of Single-Sided Heterojunction & Double-Sided Heterojunction. Can anyone simply explain it with ...
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0answers
71 views

Great Scott LED VU Meter circuit

I'm looking to complete one of my first electronics projects so I was looking for inspiration from youtube Great Scott and this project caught my eye. In short, his project converts the stereo signal ...
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0answers
49 views

Can I use Highspeed Opamp as differential clock driver?

I want to use high speed Opamp LT1364 as +/- 15V clock driver of same voltage instead of typical CMOS / CCD clock drivers with lower voltage and slew rate. CMRR : 90dB PSRR : 100dB Slew rate : 1kV/uS ...
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6answers
362 views

Reflect IR beam off reflector instead of emitting straight to TSOP receiver

I have a working set-up to detect beam breaks using an IR LED, modulated at 36kHz, and a TSOP receiver connected to a comparator. It outputs the count via Arduino. The range is about the width of a ...
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0answers
124 views

How to use 4N27 optocoupler? [duplicate]

I was wondering why the 4N27 optocoupler has a pin for base of the phototransistor - and of course how to connect it. I've usually dealt with PC817 optocouplers and connected them according to the ...
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1answer
52 views

Signal low delay for specific amount of time / hardware - equivalent of Arduino pulseIn() function

I have a circuit similar to the following: (Source: electronicsforu.com - Shadow Alarm: Light Sensitive Circuit) In the circuit, the output from op-amp pin 6 goes low when a shadow falls or light is ...
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1answer
35 views

How does a fiber optic receiver converts the optical signal to an electrical signal

A fiber optic receiver needs to convert the incoming optical signal to an electrical signal so it can be sampled. How is this achieved in practice? I believe a photodiode is used, but would a ...
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1answer
119 views

Three terminal LED pilot. What's the matter?

Long story short, I've purchased a 24VDC LED pilot and I've got a 12VDC pilot with three terminals instead. I was wondering what are each one of those three terminals for, the terminals have standard ...
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1answer
63 views

What could be the reason SPICE is outputting very different CTR curve for this optocoupler?

For a 4N25/26 I tried to plot the CTR vs LED Current graph by simulating the following circuit. To obtain results similar to the one in the datasheet I keep Vce constant at 10V and sweep the forward ...
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1answer
183 views

Opto-coupler circuit - selection of resitor [duplicate]

I have a circuit like below. I wanted to know how these resistance values were calculated. I wanted to use 12V/24V in place of 9V. Let me know selection of opto-coupler and resistance value.
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1answer
70 views

Interfacing a microcontroller digital IO

I'm working with some microcontrollers, and I'm quite confused about how to interface the digital I/O. I've already see some projects with opto-couplers on outputs, other ones with buffers, so I'm ...
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1answer
19 views

Relation for the current generated by a photo-diode in photo-conductive mode

If a photodiode with responsivity R is operated in photo-conductive mode with reverse bias voltage Vb and load resistance Rld what relation gives the output current from the photo-diode flowing ...
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1answer
21 views

Esp8226 with opto mosfet switch LBA110

I want to switch AC load by LBA110 because it has NC switch pole and tiny side. I tried to read datasheet, but with my bad knowledge about electric, I can not find out how to make it work. Is it work ...
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1answer
100 views

Increase LED Brightness

The schematic shows one row of my 16(row)x32(Col) LED matrix. Each row has 32 LEDs. I'm Scanning rows @ 1/16th rate.I'm using a PIC micro controller. I use 3V LEDs. The problem is LEDs are dim. How ...
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2answers
54 views

What bias voltage is applied to a PIN photodiode when connected only to multimeter

If I take just a PIN photodiode (e.g. BPW34 FAS ) and connect a multimeter to its terminals to measure current, for example: expose the photodiode to the sunlight and read current of ~1 mA on the ...
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1answer
63 views

Photodiode current vs. irradiance and finding upper limit current

1.) What equation could be used to calculate, or make a decent estimate of the current produced by a photo-diode from incident irradiance and its operating parameters. For example for this PIN photo-...
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1answer
96 views

Reverse function optocoupler in series with physical NC switch?

I've read this answer (reverse function optocoupler) but my case is different: I've got a CNC mini lathe. I have a limit switch on one of the lathe's axis ends (X+) wired as NC to my Gecko G540 ...
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0answers
95 views

Light sensor using transistor

I am trying to create a light sensor circuit using 2N3904 transistor but current is not passing through RL what is error in my circuit?
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0answers
46 views

Can't get my led bulb to turn on using triac and optocoupler

I have made the below circuit but my LED bulb won't turn on, although circuit works fine if replace the led bulb with a small led and ac supply with 5v dc supply. Can someone guide me in a right ...
2
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1answer
168 views

Driving IRF9530 MOSFET with 5V

I want to drive the IRF9530 P-Channel FET with 5V PIC microcontroller. My load is 3.2A. schemtic shows one row in my LED matrix. Scanning @ 1/16th rate, so peak current per LED will be 64mA and the ...
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2answers
76 views

Improve Brightness in LED Multiplex

I’m doing a 16 rows & 48 column LED matrix design. The attachment shows only one row & some columns. I’m scanning rows @ 1/16th rate. Designed for 4mA average current to the LEDs. I’m doing a ...
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1answer
41 views

Is this opto input current sized wrong and can it have such symptoms?

I have been using 4N26 opto for some time for a trigger input of a module. Vin is fixed 40Hz 0..5V pulse with %50 duty cycle. OUT goes to trigger of a module. Below is the schematics: Among ...
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2answers
114 views

LED Matrix Leakage LEDs

I'm doing a LED matrix design and it's a cathode row design. Attached is a picture of my matrix design. The design works ok and I can show any pattern in the matrix. The problem is when a leak LED ...
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2answers
138 views

what limits the maximum voltage of this optocoupler (6N137)?

In the datasheet it is stated that the maximum VCC voltage is +5.5V.(https://www.vishay.com/docs/84732/6n137.pdf) Because ive been told to question everything (and i have enought of them to kill one ...
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1answer
125 views

Why isn't the saturation current of a photodiode the same as its short circuit current?

The formula I see everywhere is: $$ I_{sat} = \frac{V_{bias}}{R_L} $$ But this seems incomplete for the following reason: The larger the resistance is the smaller the saturation current, it stands ...
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0answers
536 views

Optocoupler 24V input misbehaving

I have an optocoupler circuit that is used to accept 24V input (100 ms pulses) and interfaced to a microcontroller. The schematic is as follows: Opto: BL817C or TLP621. TLP621 datasheet As per my ...
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2answers
204 views

Optocoupler to drive LEDs (maybe with transistor)

I wonder if there is some simple solution to drive LEDs powered from single rectified voltage. Assume AC is 220 V, each LEDs is 3.0 - 3.2 V 150 mA. I reckon series connection made it simpler but not ...
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0answers
35 views

Choosing a camera for near-infra-red illumination analysis

Which parameters are important to look for in camera specs./data-sheets if it will be used for irradiance pattern analysis from near infra-red sources. Typical spectra range of interest is from ~700nm ...
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0answers
27 views

Optocoupler or transistor.. which is good for high load relays using Arduino

I'm a newbie or a beginner with electronic stuffs. I'm trying to switch on/off a 1.5hp water pump using Arduino. I've got a 40 amps solid state relay in which the coil voltage is 12-36v. So for that I'...
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2answers
37 views

How will the resistance of this Evaluation Module affect the measurements of the current produced by this photodiode?

A little context: This is part of a bigger project about glowing algae, my job is to design a photodiode array to measure the amount of light the algae produce in response to movement. I have a good ...
2
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2answers
396 views

Help understanding power ratings in optocoupler datasheet

I want to understand this the datasheet for the Everlight EL817 optocoupler but don't know what is the maximum power can the output hold. I see an optocoupler as a kind of switch that closes a ...
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2answers
97 views

Better resolution with photodiode (LTR-536AD)

I want to build something like a fog-sensor. I'm using a laser and on the other end (~20m) I have a LTR-536AD photodiode. I hooked the photodiode to an arduino and was monitoring the voltage. My ...
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2answers
113 views

Measure laser with photoresistor (LDR)?

I want to make a simple setum, where I can measure the opacity of air. I want to use a simple laserbeam, which I shoot across the room, and on the other side I want to measure how much is blocked/...
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1answer
68 views

How is optimum series resistor of an optocoupler sized?

I want to learn how to size the series resistor for this optocoupler which has a high CTR. I will use Arduino's 5V digital output pins for eight of this coupler so I really want to source necessary ...
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2answers
110 views

Trouble changing an optocoupler without changing circuit functionality.

As a part of a circuit an optocoupler was driving the gate of a MOSFET as follows: Now I need to change the above opto with a 4N46 darlington one. I'm not familiar with these much and having ...
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1answer
181 views

What does “off-state output terminal voltage” in optocouplers mean?

I was looking at possible options of what optocouplers to use in my project. I was looking at these parts. https://www.fairchildsemi.com/search/?searchText=MOC3023-M#N=&&Nao=0&&Ntk=...
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2answers
71 views

optical path resonance distance measurement device, super useful for open source hardware if it would work [closed]

My head just tends to be full of open hardware and open manufacturing stuff, and one idea I have had for years and always wanted to try, but never could for want of access to an electronics lab, is a ...
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1answer
324 views

LOGIC GATES and logic circuits in a calculator

i am tasked to do a circuit using logic gates regarding the work of a calculator. it is said that how can we make number 3 shown in a calculator represented by logic gates. can someone help me? i ...
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2answers
95 views

Identifying mystery dual channel opto detector?

How do I identify if a component is a photo diode or photo transistor? I have a three lead component removed from an old mouse where it was used to do quadrature encoding of the scroll wheel (a normal ...
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1answer
132 views

MID400 used in “Unsaturated” Mode

I've been spec'd a MID400 in a high voltage A/C power monitor circuit. After receiving the prototype (board is done), I've determined this device is for power on/off application. Problem is I need to ...
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1answer
217 views

What is comparison of readout times of global and rolling shutter cameras? [closed]

Rolling shutter will take more time because of sequential readout and global will take less time.But what are the exact values of image readout time?