Questions tagged [photodiode]

A photodiode converts light to an electric current.

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40 views

How to simulate the CNY70 IR reflectometer with TINA or LTSpice

How can I model the CNY70 IR reflectometer from Vishay (click here for datasheet) using TINA or LTSpice. In particular, I would like to simulate the circuit shown below: The 4pins on the left side ...
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1answer
31 views

Switch Configuration for Variable Gain Photodiode Amplifier

In this article here: https://www.analog.com/en/technical-articles/optimizing-precision-photodiode-sensor-circuit-design.html# It states: However, I don't understand the rather critical line "...
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47 views

Why when i put a voltage through my photodiode its sensitivity doesn't change?

I have a photodiode that I want to experiment; the problem is that when no voltage is applied to the circuit I get a voltage through the resistor of around 0.3V that change if I apply light. For any ...
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2answers
47 views

Confused about photodiode current

I am confused about the photodiode current voltage diagram. According to this diagram the current at zero bias is down->reverse current.How is that even possible? At photovoltaic mode isnt the ...
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39 views

IR modulation with photodiodes multiplexing

I have 100 IR photodiodes that I would like to multiplex to one (or the fewest achievable) transimpedance amplifier(s), both for space and price constraints. I am aware of the capacitance and noise ...
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2answers
597 views

Amplify difference between two photodiodes

I have two adjacent photodiodes in photovoltaic mode, with two transimpedance amplifiers. Unfortunately, my MCU (nRF52840) is one meter away, and I expect a fair amount of noise to enter the system. ...
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1answer
19 views

AQW610EAH-PhotoMos Relay

Can we apply voltage across 1 and 2 pins to control normally closed (N.C) and to pins 3 and 4 for normally open (N.O) at the same time in AQW610EAH ICs (pin diagram of that IC above)? Or only one N.C ...
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3answers
55 views

Photodiodes: Measuring Low Optical Power vs Dark Current Contradiction

Taken from: http://www.geni-uv.com/download/products/GUVV-T20GD-U.pdf I'm trying to do some estimates here and I've run into something that seemingly doesn't make sense. In the table above, it states ...
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3answers
731 views

How to select LEDs for use as colour selective photodiodes?

When selecting LEDs for use as photodiodes, are there general guidelines that one can use to increase the odds that a more suitable LED is selected? For example: Does diffuse or clear impact ...
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29 views

Monitor Photodiode polarity convention

I have Monitor Photodiode specs that claim the following: MPD Reverse Voltage: -10V Min, -3V Max MPD Forward Current: 0mA Min, 10 mA Max What is the convention for measuring this voltage and ...
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1answer
69 views

Analog circuit for a photo sensor

I'm personally developing an analog circuit for a photo sensor using very cheap op-amp. My biggest motivation for my circuit is to design it cheaply as much as possible. My main op-amp is a TL071. ...
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2answers
58 views

Not accurate readings when connecting OpAmp AD822 to ADC MCP3008

for my project, I am using a photodiode, that I connected to the AD822 OpAmp. This OpAmp should then be connected to the MCP3008 ADC. I am reading the data from the MCP3008 with a RaspberryPi. I am ...
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1answer
118 views

Small feedback capacitor in photodiode amplifier

I'm designing a transimpedence circuit with a photodiode. Op-amp: LTC6268 (GBW = 500MHz) Photodiode: SFH2700 A1 (C_j = 4.6pF, max current = 1.5uA) Required bandwidth: 2MHz Using the calculation from ...
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2answers
80 views

Simulating Photodiode sensor in LTspice

I am designing a current source that is going to control LED. With help of the DAC and microcontroller, I generate a voltage that goes to OP-amplifier, and afterward, I am opening my NMOS transistor. ...
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2answers
59 views

Photosensitive Diode or photo resistor?

As I understand it, a photosensitive diode generates a small current with light. I ordered these off Amazon: https://www.amazon.com/gp/product/B01F3TU2XC/ref=ask_ql_qh_dp_hza These change resistance ...
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1answer
72 views

Can the direct current output of a photodiode pass through a capacitor? If so what effect are they having in this circuit?

I am studying RC filtering in order to try and understand this circuit which was previously discussed in(What kind of filtering does this op-amp perform?). The answers gave advice on testing the ...
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1answer
46 views

Transfer Function of Photodiode

I am trying to obtain the transfer function for a photodiode. Since I couldn't find any standard result online, I figured I would try to obtain it from the circuit equivalent shown below, but I am ...
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1answer
47 views

Measuring Voltage from Photodiode with OpAmp

I am trying to measure the voltage coming out from my OpAmp after connecting it to my Photodiode. As a Photodiode I am using the BPW34S from Vishay and the Op Amp is the AD822ANZ from Analog Devices. ...
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1answer
35 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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44 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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3answers
80 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
80 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
37 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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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
107 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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30 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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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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45 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
40 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 ...
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1answer
134 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
74 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
41 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
50 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
353 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
94 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
133 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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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
88 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
159 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
71 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
35 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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125 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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51 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
57 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 ...

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