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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 ...
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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 ...
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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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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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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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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,...
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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 ...
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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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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 ...
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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 ...
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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 ...
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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 ...
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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 ...