Questions tagged [optoelectronics]
Components, circuits, or systems that convert between electrical and optical (light) energy.
0
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56 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?
2
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0answers
34 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
99 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
53 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 ...
1
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1answer
32 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 ...
1
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2answers
61 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 ...
1
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2answers
54 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
54 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 ...
1
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0answers
82 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 ...
0
votes
2answers
97 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
29 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
20 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'...
0
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2answers
29 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
votes
2answers
71 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
74 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
59 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
57 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
65 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 ...
0
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1answer
62 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=...
-1
votes
2answers
69 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 ...
0
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1answer
180 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 ...
0
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2answers
79 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 ...
0
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1answer
68 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 ...
0
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1answer
126 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?
2
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4answers
937 views
Why we use two photodiodes as optoisolator or optocoupler?
Why do we need two photodiodes in order to create an optoisolator or optocoupler? Many sources say that it is to compensate for the non-linearity of the diodes, but is there any explanation based on ...
0
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0answers
49 views
How to read spectral responsivity curve?
I'm currently trying to work with TCS3200 color sensor, I came across a spectral responsivity curve in the datasheet.
Suppose, if I place a color with RGB value 255,0,0 that will be around 640-670nm. ...
1
vote
2answers
303 views
24 VAC Detection Using Optocoupler
I have been using an HCPL3700 to detect 24VAC, but they are large and relatively expensive. I have tested the design shown in the figure (AC input to the diode, and measuring output collector-emitter ...
0
votes
1answer
171 views
Design of output stage for CNY70 reflective sensor
I have built the following circuit for a reflective sensor:
The resistor \$R_D\$ has been given the value 200 \$\Omega\$ and the resistor \$R_T\$ is to be dimensioned. \$V_{CC}\$ is 5 V.
I have ...
2
votes
1answer
127 views
Questions about CNY70 Reflective Optical Sensor datasheet
I am using the CNY70 for a project, but i need information from the datasheet. In Figure 11, which i have added below, the relative collector current, \$I_{Crel}\$, is shown versus the displacement, s,...
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votes
2answers
108 views
Automatic room light controller with IR sensor
(Schematic source: Electronics Hub)
In this circuit sensor is not working.using (4*1.5)v cells as supply.without connecting the transmitter and receiver elements,in the o/p led glows.i have connected ...
2
votes
1answer
322 views
SWD optoisolation problem
I have designed the following optoisolator for SWD interfacing with an STM32 device and J-LINK programmer:
This is the generic schematic:
And this is a single optoisolator schematic:
I am not able ...
5
votes
2answers
582 views
Typical wavelength range for solar cell measurement
Why is a wavelength range of 300nm-1100nm usually used to investigate the properties of solar cells (EQE, current generated, etc.)? Is it to reduce spectral impact? I also don't understand what is ...
0
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1answer
91 views
Detect if the load is present on this circuit
Is there a way to detect if the load is conected on the circuit above?
(The other load should be connected to the F Pad, sorry for the mistake).
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0answers
103 views
Low cost low speed fiber optic connection for embedded applications
I would like to use a fiber connection to send data between two nodes. The nodes would typically have a 8 or 32 bit micro controller. I need data rate of 2 Mbps or higher and distance is about 100 ...
5
votes
1answer
372 views
Q: Check if an LED in my circuit is still “good”
I have an electrical circuit which uses an LED, connected to a µC, to show the status of an x-ray source in another room. Obviously this LED is important to have in a working condition.
Now, LEDs can ...
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0answers
64 views
Material choice / optical properties for solar panel cover (glass/perspex/lexan)
First off I realise this is sort-of off-topic but this was the most relevant stack site I could think of...
I have a Bosch solar panel which was damaged by couriers, the glass covering was shattered ...
0
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1answer
276 views
4n25/35 optocoupler detect led on/off
Hey all i am just wondering if my drawing below is correct in order to have an arduino detect an on or off led on another board using a optocoupler?
My thoughts of the above drawing is that when the ...
0
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2answers
952 views
LED response time (time to warm up)
Can someone help me to explain why LED have better response time when compare with other light source (ex:fluorescent lightbulb). Because their structure or anything else? Thanks everyone so much.
1
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1answer
158 views
How Gigabit Ethernet is achieved in fiber optics?
I understand how 1000BaseT works on Cat 5 cables: It uses clock rate at 125 MHz, 4D-PAM5 data encoding to transmit 2 bit per cycle and it uses the four pairs of the cable. The math is quite simple: ...
0
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3answers
165 views
Why is this circuit isolated?
From Linear Optical Isolation for Safe Sensor Operation:
Are the three grounds indicated all connected?
Are the four Vcc indicated all connected?
If the above is all true, how could this be an ...
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2answers
764 views
Minimal component set to build a computer mouse [closed]
I am searching for a DIY set to build an optical mouse.
What I need is a bare minimum set, giving the ability to build
a very small mouse without buttons, and possibly for beginners.
Should be ...
0
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1answer
301 views
Isolating Digital IO from Microcontroller
I have designed an Embedded System in which the PCB has both Non-Isolated and Isolated DC DC converter.
I am taking a 24V DC Supply from a PLC Device. Converting it to 3.3V with a Non -Isolated DC DC ...
0
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0answers
49 views
Check if signal drifts are temperature related
Let’s say I have an output signal vs time plot data of some opto-electrical device (a black box for me). If the device is exposed to sunlight the signal starts to drift to higher values.
Is there a ...
0
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1answer
500 views
Solid angle measurement conditions for radiant intensity specification in IR-LED's data-sheets
For some IR-LED's their data-sheets state Radiant Intensity and the conditions under which
that number was obtained, indicating also which solid angle was used for the measurement.
For example, this ...
0
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1answer
68 views
How to connect chip pin to either vcc or groud externally?
I have a board that i use ic which one pin need to be externally decided to be connected to VCC or ground based on LED lightening
The schematic use this symbol for a connector to indicate this
How ...
0
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1answer
147 views
Test an LCD for missing segments without looking at the screen? [closed]
I have a product with an LCD screen that sometimes fails with missing segments.
I will test the product for a long time to replicate the failure.
I will test many at once.
I don't want to sit watching ...
0
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2answers
258 views
What can I use instead of a CD4007 transistor? [closed]
What can I use instead of a CD4007 transistor, or how can I simply design a "20 watt or larger" speaker using a "TBA810" or any available widely available and used IC?
I found this circuit: Touch ...
2
votes
3answers
698 views
pc817 large emiter collector voltage drop in saturation
I'm experimenting with a very simple circuit with a PC817 optocoupler. I just want to turn on an LED with the optocoupler output, but the bright is really low in comparison to a direct drive of the ...
1
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2answers
109 views
Lowest noise, low frequency, cheap photodetector configuration? [closed]
Currently we are measuring the position of a mechanical beam by illuminating it with light from an IR diode and using two phototransistors to measure the difference between light passing over and ...
1
vote
1answer
920 views
How is the H11AA1 ic working with AC mains voltage?
I am making an arduino controlled fan speed controller that would digitally control the speed of my ceiling fan working on 230 VAC and 50 Hz. I am using the following circuit which is designed for ...
