Questions tagged [photodiode]
A photodiode converts light to an electric current.
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59 views
PCB dual LED emitter, TIA and voltage regulator (beginner)
Does this PCB look good for this operation?
The schematic is attached.
I have a voltage regulator connectected to an LED emitter. Voltage regulator to TIA . TIA then is attached to active high pass ...
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2answers
39 views
Driving Avalanche Photodiodes (PCBs)
I am using Avalanche Photodiodes and I was told that they use a much higher voltage then standard photodiodes and I was wondering if I need a High Voltage PCB to drive them? I am currently just using ...
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2answers
48 views
Photodiode Output measurement
I'm using Hamamatshu s8559 photodiode to convert x-rays into it's respective energy.
I'm using a 10 bit ADC converter.
The problem I'm facing is I have no relationship between the Photo-current ...
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2answers
80 views
Very low current (<10 microamps) darkness detector circuit that turns off in light
I've made a device that lights an LED at a very low current (<10 microamps) as a very dim indicator for use in the dark.
At its simplest, the circuit is a 3V coin battery + resistor (300K-1M ...
2
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1answer
49 views
How to use my bits to transmit this photodiode signal in the most efficient way possible? [closed]
Suppose I have photodiode with a Dark Current of 5 pA and that using the NEP of that photodiode at some frequency \$\lambda\$ I determined that the smallest signal I could detect was of 1 pA.
First ...
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1answer
19 views
Phototransistor and Photodiodes capacitances when some in an array sense light
I'm using phototransistors to sense low speed data (about 7 bits a second). With one phototransistor and a 300K resistor, I found my sweet spot and can transmit correct data with lazer.
I find if the ...
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1answer
78 views
Can you connect multiple photodiodes in parallel and treat it as one?
Im working on an IR sensor based off of the Texas Instr. particle sensor (TIDA-00378). They use just one photodiode in their design. I would like to use multiple photodiodes, lined up with multiple ...
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1answer
35 views
making a photodiode module
I am trying to do stimulated Raman scattering microscopy. In this experiment two pulsed laser beams are used . The wavelength of these two laser beams is tuned to match a specific Raman frequency of ...
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1answer
49 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 ...
3
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5answers
113 views
Please explain this formula for the relationship between bandwidth and the temporal response of a photodetector
I am reading "Optoelectronic Sensors" by Didier Decoster and Joseph Harari.
At section 1.8.2 they start explaining the relationship between rise time and bandwidth, and they give a very weird formula ...
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3answers
826 views
Forward drop of diode vs forward drop of LED
It is always said that forward voltage drop in the diode is around 0.7 volts. LED also being a diode, why does it have a greater forward voltage drop of around 3 Volts?
What is the model of LED that ...
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0answers
44 views
LED output with Photodiode and Function Generator
Some of my student and I are designing a Physics experiment involving a high power LED, a square wave from function generator (50 ohm output impedance) and a digital oscilloscope (1 MOhm imput ...
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0answers
43 views
How to calculate the current produced by a solar panel?
The equation for calculating current when given voltage and temperature is known as the 5-Parameter model ie.
\$I = I_{ph} - I_o[\exp(\frac{V + R_sI}{nV_t})-1] - (\frac{V+R_sI}{R_{sh}})\$
Since this ...
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1answer
64 views
How does a camera pixel accumulate charge (colour)?
I refer to the Wikipedia entry for a CMOS camera sensor's individual pixel. There is a schematic like so:-
and a statement that:-
The read-out transistor, Msf, acts as a buffer (specifically, a ...
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1answer
41 views
Explanation of 5 Parameter Model for Solar Cells
I am having a hard time understanding this equation, the 5 Parameter model for photovoltaic cells.
\$I = I_{ph} - I_o[\exp(\frac{V + R_sI}{nV_t})-1] - (\frac{V+R_sI}{R_{sh}})\$
My goal is to apply a ...
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0answers
54 views
Estimate minimum detectable light pulse in a photodiode (5 ms, 44 kHz modulated)?
I'll use an IR LED modulated at 44 kHz to illuminate particles in air or water, and will use a silicon photodiode to detect weak pulses of scattered light as they pass through the LED's collimated ...
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1answer
29 views
Output changes wildly with input voltage in photodiode circuit
I am currently analyzing a photodiode sensor input circuit (not designed by me, but schematics drawn from a commercial product). I am currently simulating the circuit on TINA TI. While experimenting ...
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2answers
26 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 ...
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1answer
59 views
How does this op-amp photodiode circuit behave?
I am trying to understand the inner workings of a photoelectric object sensor I have in my hands. (modulated with 24 kHz) Here is the very beginning of the receiver part:
simulate this circuit –...
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0answers
77 views
Making LED flash from steady-state signal
I am looking to design a simple circuit that detect objects placed in a spot. So far, the circuit uses simple IR LED and photodiode to detect the object placed between them. The voltage developed in ...
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1answer
28 views
Resistor on transimpedance amplifier input?
I am currently examining an expired patent file of a photoelectric sensor. The file includes the circuit, I am trying to understand it with my limited analog electronics knowledge:
Patent no: ...
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0answers
80 views
PV cells (photovoltaic) I-V curve plot simulation
I am trying to plot the I-V curve using python because that helps me in understanding PV cells / solar panels (and diodes as a general thing).
I know the formulas ...
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1answer
15 views
How to properly use an OPB917BOCZ photoswitch?
I am building a weather station with an anemometer. I have an OPB917BOCZ photoswitch on-hand that I would like to use as the tachometer if possible. However, I can't seem to have any luck with it.
...
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1answer
55 views
How to connect a 2 pin photodiode?
Initially, I have used 3 pin photodiodes, where the anode is connected to the resistor and has a wire which goes to group and the other goes to an analogue input to read the voltage. The cathode is ...
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3answers
91 views
Correct use of op-amp to amplify photodiode in reverse bias
So I have a photodiode in reverse bias, from which I intend to measure my pulse.
Currently, my schematic looks as follows:
simulate this circuit – Schematic created using CircuitLab
Weirdly,...
3
votes
4answers
787 views
How to tell how sensitive a photodiode is?
I am looking to buy some new photodiodes for a project. Currently, I have been using expensive photodiodes with a picosecond level rise and fall time and a very small area to pick up light. The ...
2
votes
4answers
510 views
Photodiode almost no mV at analog port
So I have bought a photodiode, which I intend to hook up to the analog port of my Arduino, so that I can measure differences in the light that the photodiode picks up.
I realized, that when I don't ...
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1answer
57 views
High speed photodiode for laser pulse width measurement
I want to measure the temporal width of a Q-Switched laser (which should be close to 5 ns) and the delay between two lasers that I send in my experiment. The delay is between 1 ns and 1 µs. Wavelength ...
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1answer
37 views
where do i find max short circuit current of photodiode?
I'm trying to convert the current signal from a photodiode to voltage through a transimpedence amplifier.
The photodiode is put in photovoltaic mode in order to get the greatest accuracy and lowest ...
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1answer
39 views
Schematics of PIN Photodiode interfacing with an ADC
This question is in continuation of my previous question.
I am moving forward with PCB designing now. I have selected low input-bias current op-amp AD8616 for converting current signal into voltage. ...
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1answer
127 views
Laser Microphone setup
I am currently constructing a laser microphone using 5mW red laser pointer source based on the idea below, not directly output to a speakers or headphones, but the signals must be fed into computer ...
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1answer
37 views
The breakdown voltage of APDs
what does the breakdown voltage of an APD tell me? I know certain methods how to determine it but, what happens after reaching that point?
More specific: Is the gain afterwards constant or still ...
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1answer
97 views
Why is this photodiode operated in reverse bias
Referring to the following document by NXP on figure 9. The cathode of a given photodiode is connected to the transimpedance amplifier in forward bias.
To me, this seems wrong, as almost every ...
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2answers
70 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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1answer
83 views
Correct use of transimpedance amp
So I realized that it might become a necessity for me to use a transimpedance amplifier for a pulse watch that I intend to make.
Some background:
The pulse watch shoots light at 940 and 660nm at ...
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1answer
56 views
Does this photodiode need an operational amplifier?
I'm trying to make a circuit for a pulse watch, which should be capable of measuring blood SpO2. I use 2 LEDs for each wavelength (respectively 660nm and 940nm) to shine at the upper wrist.
The ...
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1answer
76 views
Photodiode temperature compensation
The goal is to design a circuit that can accurately measure light intensity with little temperature dependency.
Common application uses photodiodes to do so.
Photodiodes can be measured either in ...
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1answer
153 views
Arduino breakout schematic for FDS100 Photodiode
This is the first time I'm drawing a schematic, thus why this question seeks to get clarification from you experienced engineers :-)
A little background information:
I'm trying to draw a circuit ...
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0answers
47 views
About measurement of pulse using oscilloscope [duplicate]
When I measured the optical pulse using photo-detector and oscilloscope, some negative voltage was measured after strong peak.
What did I get negative voltage?
How is it possible?
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0answers
45 views
Electronics interface circuit for PIN Photodiode
I am designing an interfacing circuit for PIN photodiode which will be used in NIR spectrophotometer project. The PIN diode is <...
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2answers
44 views
Photodiode in photoconductive vs photovolatic configuration
I want to use a photodiode to measure light intensity, but I am not sure if the photodiode should be used in photoconductive or photovoltaic mode.
From my understanding the photovoltaic ...
1
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2answers
86 views
Photodiode connection to ADC
I am designing a product where an ambient light sensor is used to adjust the LCD's brightness.
The following circuit is implemented to read the light sensor. The ...
1
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0answers
36 views
Generate ultrashort rise times with photoconductive switch or photodiode
I am trying to produce voltage pulses with very short rise time (<15 ps), medium width (20 ns) and amplitudes up to 15 V. As a promising candidate I selected photoconductive switches and ultrafast ...
2
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1answer
36 views
PIN diode in RF switching vs. PIN diode used as photodiode
From what I understand, there are traditional photodiode components that are designed with PIN diodes, in which the gate is activated by light saturation. For a PIN diode component made for RF ...
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3answers
155 views
Are IR emitter frequencies adjustable? Can modulation of the emitter variate material absorption properties?
A common LED emitter, Gallium Arsenide, apparently has a wavelength of about 760 nm. Then on the receiving end, there is a filtering circuit to eliminate ambient IR and to demodulate the message. Can ...
2
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3answers
95 views
Photodiode gate circuit noise
I'm building a chronometer for high speed projectile speed measurement. Currently i'm in the process of designing the projectile detection gate. It needs to be able to detect obstructions in light for ...
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1answer
76 views
visible light communication data reception
My project is on visible light communication. I use a 555 timer circuit to modulate data with 200 KHz signal using a 3 watt LED.
At the receiver I use a photodiode (PS100-6-CER2PIN First Sensor ...
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5answers
1k views
Infrared LED and Photodiodes
I am currently working on a project that uses an IR LED and a photodiode in a proximity sensor configuration (shown below). My question is, I have read some sites that state that your human body ...
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1answer
45 views
Can a photodiode tolerate a reverse bias beyond its specification
While searching a literature related to my experiment I come across this paper https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4424026/pdf/PP_PP201500119.pdf . On the page 27 under the section SRS ...
2
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2answers
207 views
High-speed Infrared UART link with photodiode
I need short-distance (about few centimeters) wireless IR UART link with 250k+ baud. I tried to use phototransistor (assume Q1 is phototransistor). Q3 is used to prevent inverting signal.
simulate ...
