Questions tagged [photodiode]

A photodiode converts light to an electric current.

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1answer
24 views

Bias T for modulation of VCSEL laserdiode

For my project, I would like to design a Bias Tee for a VCSEL laserdiode, because a modulation is required. The bandwidth is 20 KHz - 10 MHz. My steps are shown below: As a reference, I have used the ...
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43 views

Operational amplifier - why average voltage is not stright related to pulse to duty cycle?

I have a strange problem, that I cant find an answer. I have slow photodiode (about 2MHz) and fast, pulsed laser light source (pulses 10 to 500ns). Im trying to measure optical output power. To do it ...
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29 views

How to find the manufacturer and component details of a commercially available FDA cleared pulse oximeter sensor LED and photodiode?

I am currently exploring ideas to build a pulse oximeter with (1) a wrist watch containing the PCB, microcontroller, battery, and female micro-USB and (2) a disposable fingertip probe containing 2 LED ...
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3answers
77 views

Can LED strips be used as photodetectors?

As I did not find any photodiode/PD strips available, I am wondering if it would be possible to use LED strips as photodetectors. And if yes, which type of LED strip could be used for that purpose? My ...
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2answers
79 views

Will this photodiode circuit filter this frequency?

I have the following circuit with a photodiode and an LM358P where I intend to blink an LED at around 20kHz. I want to work on it. I have made a calculation through 1/(2piRC), and got something around ...
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1answer
35 views

is it possible linear response photodiode amplifier using 2n3819

This is a typical jfet circuit to amplify the photodiode signal. Is this simply the photovoltaic voltage generated by the photodiode? My understanding is this is highly non-linear since the voltage ...
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0answers
45 views

Understanding photodiode modes and practical effect on noise vs response time tradeoffs for audio applications

I am an experimental musician with admittedly very little electronics experience (but I do have a mathematics degree) trying to find a decent photodiode for a project where I send audio signals via ...
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0answers
21 views

carrier concentration of PN junction [duplicate]

i am trying to calculate these formulas: -and- (p-side: x < -xp , n-side: x > xn) But i wonder, how can i find pn0 and np0 Thanks in advance.
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2answers
100 views

Increasing sensitivity of photodiode amplifier

I have build a 2-stage amplifier circuit for amplifying the current from an InGaAs photodiode. It uses 2 OPA4350 op-amps. The first stage is a TIA with a feedback resistor = 1MΩ. The 2nd stage is a ...
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27 views

Photodetector and low noise amplifier acting as low pass filter

I need some basic advice for impedance matching: I have a photodetector (Det01CFC from Thorlabs, https://www.thorlabs.com/drawings/275cb418cdc2cf1f-A2E46103-D9C0-3581-4553E3D3CA93AD83/DET01CFC-Manual....
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1answer
44 views

Impedance matching for broad bandwidth voltage amplifier

I need some basic advice for impedance matching: I have a photodetector (Det01CFC from Thorlabs) that generates a current. For my experiment, I would like to amplify this signal with an amplifier. The ...
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2answers
65 views

Parallel resistor before voltage amplifier

For my project, I would like to amplify the output from a photodetector for subsequent analysis with an oscilloscope. The output of the photodetector is a current. Since we are using a voltage-...
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0answers
70 views

Current sensor that works in 0nA-250nA range?

Is there any current sensor capable of sense very low current ranges from 0nA to 250nA? I would need to sense the current produced by this photodiode: GVGR-S11SD (http://www.geni-uv.com/download/...
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38 views

carrier concentration - distance graph of PN junction

i am trying to plot the distance-carrier_concentration graph above with these formulas: -and- (p-side: x < -xp , n-side: x > xn) But i could draw only red lines on the graphs with these ...
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1answer
39 views

Photodiode Direction Sensitivity

I'm trying to create a setup where I would have xrays emitted through a photodiode (the non sensitive side). I do not want the photodiode to detect these xrays going through it, only the xrays which ...
2
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1answer
117 views

Accuracy of manufactured photocells (LDR) with respect to light intensity

I was looking through photocell (photoresistors) datasheets, like for instance the NORPS-12, especially the graphic on resistance value versus light intensity. In no datasheet could I find information ...
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3answers
72 views

Photodiode draws current from op-amp input

I am trying to measure light intensity using a photodiode (S1336-18BQ) connected to an op-amp (LF412CP) in transimpedance amplifier configuration. I couldn't get it to work correctly, so I started ...
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1answer
39 views

Existence of input signal to LED at photodiode output

I try to make simple LED/photodiode circuit by arduino and 741 op amp. I used mid-IR LED by 200mA current and suitable photodiode for it. I wanted make pulsed signal by digital output of Arduino UNO ...
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1answer
45 views

Photodiode operating modes - confusion about wording

The more I read about the operating modes of photodiodes, the more confused I get since it seems that people are using the same wording for different stuff. Please consider photoconductive (PC) mode ...
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2answers
321 views

Detect an IR signal with a photodiode to use it with a microcontroller

I am trying to detect an IR signal with a photodiode to connect it to my STM32F411 and use it as a trigger signal. The signal I send are two pulses at 500 kHz which looks like this: I am using a ...
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3answers
1k views

How fast is a photoresistor?

I am trying to build a skipping rope jumps counter. My preliminary design consists of an LDR, a laser diode, and sn Arduino. Basically, the LDR and the laser diode are placed exactly opposite to each ...
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2answers
68 views

Working principle confusion based on the photodiode, phototransistor and LED circuit

I need help understanding the working principle of this circuit that I simulated in Multisim. I'm doing this for my lab report. When the switch is closed, the photodiode, phototransistor and LED are ...
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4answers
127 views

Light sensor detecting when the lights turns on AND when the light turns off

I would like to create a circuit using photodiode that detects when the lights turn on AND when the lights turn off. The output should look something like that: I want to create the simplest possible ...
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0answers
26 views

Need Help with the transistor configuration? Biasing methodology used in circuit?

I am confused about how this circuit works, the circuit is the instrumentation for IR sensor even I have never encountered the such biasing, the IR led is activated with the pulse of 150 us the output ...
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1answer
75 views

Why does the high reverse bias voltage in a PIN diode circuit not damage the op-amp?

In this circuit designed to measure high frequency light pulses, the 30V high voltage bias input has a direct connection to the inverting input of the op-amp, despite also being connected to the ...
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1answer
128 views

opt101 (photodiode) adjust voltage output

I'm using the popular OPT101 photodiode with 5V. How can I scale the output between 0 and 5V (or as close to that range as possible)? Now the output is ca 0-400mV (maximum is room light here). I'm a ...
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1answer
67 views

Long distance required between photodetector and TIA

I have a circuit that incorporates a 40 channel InGaAs (IR) photodetector array (https://www.hamamatsu.com/eu/en/product/type/G8909-01/index.html). I have a TIA design using a LTC6268-10 first stage. ...
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1answer
33 views

Please explain negative bias and “a stronger field to sweep carriers out of depletion”

I want to understand what a comment means, and I couldn't ask in a comment. In this question, someone asked why use an op-amp with a photodiode rather than just a resistor. The answers and comments ...
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2answers
116 views

How would I have destroyed these photodiodes?

I was trying to fix a light sensor module and using a diagnostics tool for it found that 1 of the 4 photodiode sensors was faulty (it was reading 0xFF.) As I don't knowwhich photodiode corresponds to ...
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18 views

Automotive Lidar optical testing

What is meant by Lidar optical testing? The optical section of Lidar contains 1)Laser diode 2)Tx/Rx optics 3)Photodiode Whether it meant testing the above sections? If so,What parameters are tested in ...
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0answers
49 views

Photodiode and Phototransistor circuit

How can I design a circuit that characterizes photodiodes and phototransistors (as output/input)? That circuit should communicate electronically over an isolated link where one side runs a low voltage ...
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0answers
15 views

A light dependent current astable multivibrator

i have basic knowledge about multivibrators and how a photodiode is operated but i'm having trouble trying to combine them into one circuit. Suppose if i am to operate the photodiode on the circuit as ...
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2answers
55 views

Low precision flash detector

I'm interested in flash detection, what would be equivalent to 1000 FPS. High speed cameras that do this are too expensive and too heavy and provide too much information. In the long run I'm going to ...
3
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3answers
237 views

What is the response current of a photodiode to an LED emitting light at different intensities?

Let's say I have one of those conventional through-hole LEDs and I'm applying a sinusoidal voltage to it. From what I understand, at a given time, the same LED is either on or off, and to virtually ...
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1answer
75 views

Applying a forward bias to a photodiode to shift output

I am using this TIA circuit and photodiode in photovoltaic mode. I'd like to modify the circuit such that at zero light a positive voltage is produced at Vout. And as more light falls on the ...
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4answers
216 views

Design of a simple transimpedance amplifier for large area photodiode

I'm a mechanical engineer, who has the luck to design an easy transimpedance amplifier circuit to convert the current of a photodiode to a voltage between 0 and 5V (without really knowing anything ...
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2answers
99 views

Would this photodiode sensor work better in series or parallel?

I am working on a photodiode small object sensor that detects and records signatures of objects passing through an array of photodiodes facing an array of IR LEDs. I am connecting the photodiodes to ...
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2answers
498 views

Photocurrent in photodiode smaller than expected

I have a question regarding the usage of the phototransistor SFH 203 P, which I want to use for a project, where I need a small fall- and rise-time. The data sheet (I think) implies that if I use the ...
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0answers
45 views

Conditional analog sample and hold (analog override?) - circuit suggestion request

Preamble: I have a LED driven by an opamp-based constant current source (CCS). It works fine, I can set up current required and it is reasonably stable. The problem is, that LED forward voltage drops ...
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2answers
5k views

Photodiode amplifier circuits - why use an op amp instead of just a resistor?

Beginner question here. I've built a photodiode light sensing circuit in class and internship such as this one: I don't understand what it is doing over a simple circuit such as this one: Can anyone ...
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2answers
185 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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1answer
151 views

LM324N transimpedance amp for photodiode: Too low output, smaller feedback resistor gives greater output, not lower

I'm trying to build an optical power meter using a photodiode in photoconductive mode and a LM324N OpAmp: simulate this circuit – Schematic created using CircuitLab However, the output voltage ...
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0answers
107 views

Confirmation of connection between TSAL5300 IR sensor and BPW34 photodiode

I need to check whether my NIR LED sensor and BPW34 photodiode connection are correct or not. Does my IR sensor have to be infront of the photodiode? I am going to place my finger on the IR sensor to ...
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1answer
74 views

Arduino - reading translated voltage gain from transimpedance amplifier

I implemented this circuit with a feedback resistance of 330 kilo ohms and a photodiode, which detects wavelengths in the infrared range. I used the LM358 to amplify the photocurrent into voltage gain....
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1answer
129 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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0answers
85 views

Simulation of photodiode in Micro-CAP 12 [duplicate]

I am beginner in simulation S.P.I.C.E. and I use the simulator Micro-CAP 12 to simulate an electric schematic. I want to simulate the photodiode PIN InGaAs IG17-series and to monitor graphically the ...
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1answer
68 views

How to connect photo diode to trans impedance amplifier?

transimpedance example here I need to design a trans-impedance amplifier to amplify the signal from a photodiode to make a PPG sensor I need a signal to acquire from the wrist. photodiode I am ...
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2answers
300 views

What options exist for a for low-latency (<1ms) photosensor?

I'm wanting to build a computer keyboard-to-display lag measuring tool using an Ardunio: User places the photosensor right-up to their computer monitor. User presses a button on the Ardunio. The ...
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0answers
19 views

Q-value in APD photodetector

I try to calculate the Q value of APD photodetector with these parameters: $$R \hspace{0.1in} (response) = 1$$ $$M \hspace{0.1in} (magnification) = 10$$ $$k \hspace{0.1in} (ionization \hspace{0.1in} ...
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2answers
189 views

Vs1838B break beam problem

So im using ESP32 to output 38khz 40% duty cycle wave to ir led and connecting a vs1838b on the other side. The vs1838b works as it outputs LOW when i send a signal from my remote. Anyways, after the ...

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