Questions tagged [photodiode]

A photodiode converts light to an electric current.

Filter by
Sorted by
Tagged with
26
votes
6answers
26k views

Does this photodiode circuit work?

Oli used this circuit in an answer, and it pops up a lot on Google images too. But does it work? If it does a theoretical explanation will be welcome.
2
votes
1answer
923 views

selecting a TIA - and using it for 60dB dynamic range

before entering in to problem: my application is a laser pulse detection, in this process when a laser pulse falls on photo diode it generates current, for which i need a Trans Impedance Amplifier (...
10
votes
2answers
24k views

How to Use SFH235 IR Photodiode Correctly?

I have an SFH235 ir photo-diode (which datasheet can be found here) and only basic knowledge of electronics. I want to connect the photodiode to an Arduino (the grand-plan is to add an ir diode and ...
3
votes
1answer
966 views

Large photodiode capacitance

I'm working with an avalanche photodiode with a 320 pF capacitance. What exactly are the downsides of suc a photodiode with large capacitance values? I assume they would be slower due to the narrower ...
4
votes
5answers
54k views

ICEO, ICBO physical interpretation in BJT

I am stuck with the equation: ICEO = (1+β) ICBO My questions are: What is the physical interpretation of this equation? Will both the currents exist simultaneously? Are any of the reverse currents ...
3
votes
0answers
893 views

Complete Noise Analysis: to find the minimum detectable signal of a TIA

Problem Statement: my aim is to digitalize a 10ns narrow pulse coming from a photo diode with current ranging from 10nA-70mA, as its impossible to cover this dynamic range of >60dB using a single TIA ...
11
votes
1answer
50k views

How do I connect a photodiode?

I'm trying to design a circuit to measure the ambient visible light (380nm to 750nm). Accuracy isn't too important. I've been looking at photodiodes, but I'm not sure how to connect them up. I need ...
3
votes
3answers
787 views

eliminating those unwanted op amp[TIA] outputs

my problem statement: i wanted to digitalize 10ns pulses from a photodiode which are in the range of current 100uA to 1mA (these were earlier much larger in range, dealt here, soon I have ...
2
votes
2answers
4k views

Electronic pendulum

I am building an electronic pendulum. I want to use a 2N2222 to power the drive coil when the pendulum bob interrupts an IR beam. The pendulum bob is magnetic and moves in reaction to the drive coil. ...
3
votes
1answer
1k views

Photodiode - Modes of Operation, Currents and Voltages

Problem Statement Consider a pin-Photodiode, whose depletion region, space charge profile and electric field profile can be visualized as follows (screenshot of the Semiconductor Applet Service by ...
7
votes
1answer
3k views

Using a solar panel for laser light detection

I've been planning on putting together a laser tag system and one of the big concerns I have is that photoresistors/phototransistors have relatively small surface areas w/r/t a human body. On the ...
1
vote
1answer
777 views

How to approximate the behavior of a phototransistor in the circuit editor?

While phototransistors are often used in this common turbidity sensor application (at least in part) because of their gain, their response is not linear since the gain will depend on the intensity of ...
1
vote
2answers
2k views

Equivalent circuit of a photodiode

What can I learn from an equivalent circuit model of photodiode like the following? I've actually gone the whole way beginning from doping semiconductors through each noise term to the amplification ...
0
votes
2answers
1k views

Simplest Light triggered relay

I am building a large array of Light Switched relays, and due to the size of the array i want to keep the part count down. Each 'Pixel module' has a 12V SPDT, bulb and an activate-on-dark circuit. ...
0
votes
0answers
43 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 ...
0
votes
2answers
3k views

How does a photodiode behave in saturation?

In my design, a photo diode is connected in reverse bias with 12V. The LDO (low-dropout) voltage regulator which is used for biasing can deliver a maximum current of 500mA My configuration: simulate ...
0
votes
1answer
165 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 ...
0
votes
2answers
1k views

Photodiode - circuit questions

I am a bit confused on a few things regarding photodiodes. Here are two circuits that I am referring to: or   For the second circuit the capacitor is not of importance. Here are my fundamental ...
0
votes
2answers
77 views

Rotating a motor according to calculated output [closed]

I have 13 photodiodes. Positive connection from battery is connected to the positive end of each photodiode. The position of photodiodes is as shown below: ...
12
votes
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 ...
5
votes
2answers
7k views

MIDI to Arduino with a 4N38 Optocoupler

I ordered a set of optocouplers the other day and was excited when they finally came in. Unfortunately, I've having a bit of trouble getting them to work. Simple on/off tasks work fine but when I ...
3
votes
2answers
2k views

Ambient light rejection from photodetecting circuit

I've built a photodetecting circuit as below: simulate this circuit – Schematic created using CircuitLab And with this circuit, I'd like to measure brightness of a blinking LED: From the left,...
6
votes
2answers
13k views

Adding Photodiode to LTspice

I am very new to LTspice. I would like to ask "How can I add a photodiode in the Ltspice?" Is ideal photodiode (or any specific) model already included in the LTspice or do I need to create third ...
2
votes
1answer
2k views

Light intensity and photodiode current

Recently i am using a LED as a photo detector . Follow by this instruction : http://makezine.com/projects/make-36-boards/how-to-use-leds-to-detect-light/ An opamp is used to convert the photocurrent ...
1
vote
2answers
7k views

Forward Bias Photodiode circuit

I have made a quick search but couldn't find anything specific around. I need to design a rudimentary circuit for a photodiode in conductive mode. I am interested in high speed rather than ...
0
votes
2answers
191 views

Experiments to convert analog 10ns pulse to digital 10ns pulse

My objective : converting laser pulses from photo diode ranging from 10nA - 100mA (60dB dynamic range of incident power) to digital format, for measuring pulse width exactly pulse width 10ns and ...
7
votes
2answers
3k views

Limiting Output Voltage of the Opamp-to avoid saturation

Problem: my photo diode recieves pulses of width 10ns-150ns and repeating at rate of 1Hz-50KHz the current from photo diode depending on incident light can go from 10nA-100mA, in a nutshell, my ...
5
votes
2answers
1k views

Reduce Input Capacitance Transimpedance

I'm designing a readout circuit for a photodiode consisting of a transimpedance amplifier. I've noticed that the photodiode has a relatively large capacitance (320 pF). Are there any tricks/...
3
votes
2answers
14k views

Calculating photodiode current based on A/W for simulation

I'd like to simulate photodiode current for a silicon photodiode, one example device the project may use has the following specifications: Based on the above plus a guess at Rs for the moment from a ...
3
votes
2answers
2k views

Can I create a multiplexed array of IR photodiodes?

I'd like to use an Arduino to read from a large number of IR photodiodes. I have seen this question: How to Use SFH235 IR Photodiode Correctly? and would like to use a similar technique to the circuit ...
3
votes
0answers
132 views

Transimpedance AMP, Active HPF, phototransistor

So this is the part where I would like the phototransistor (TEMT6000X01) to be able to clearly capture an LED with a frequency flashing on and off at 1kHz. So what I have here is a transimpedance ...
3
votes
3answers
4k views

Transimpedance Amplifier Photodiode

I have a 660nm LED powered in a separate circuit and am trying to build a photo diode using a transimpedance amplifier but I am extremely confused. I read all the articles on this site about them. ...
2
votes
1answer
678 views

Avoiding opamp saturation - working with apd

i have avalanche photo diode with which i am trying to digitalize the current from TIA through a comparator, the diode biased using a HVDCDC the source is being a 20ns laser with a PRF of 3Khz the ...
2
votes
2answers
6k views

How ICBO gets amplified to ICEO in BJT when base is open

I have been doing some reading about ICEO and ICBO, but couldn't really understand how ICBO is getting amplified (1+ beta) times to reach ICEO, in the open base condition. This is my understanding ...
2
votes
3answers
584 views

Working with current feedback opamps [CFA]

Before entering in to problem: My application is a laser pulse detection. In this process, when a laser pulse falls on a photo diode, it generates current. Later stages include a I-V conversion, gain, ...
1
vote
0answers
162 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 <...
1
vote
1answer
643 views

Influence of active area of photo diode on sensitivity

I am using a photodiode for detecting the laser. I have a question regarding the active area of the photodiode. Is less active area photodiode is less sensitive? Or it totally depends on the laser ...
1
vote
2answers
1k views

Photodiode connected in reverse?

I'm working on a photodiode circuit which has been designed by someone else a few years ago. The basics of the circuit seem simple enough, photodiode to op-amp, op-amp to ADC, ADC to FPGA. The ...
1
vote
3answers
510 views

Unused Op-Amp in Photodetector setup, but only occasionally

I am designing a modular system that will take 9 or 16 photodiode inputs, depending on its setup, and put them through an op amp. The diodes and the op amps are on different PCBs, connected by pin ...
0
votes
1answer
1k views

Do you have to put a voltage across a PV cell for it to work?

I'm studying about PV cells and I'm slightly confused. Currently, I'm learning this very simple model. I'm trying to figure out how exactly it works. Am I correct in saying that; You apply a voltage ...
0
votes
2answers
65 views

Transimpedance AMP, Active HPF, phototdiode (updated)

The original post is here Transimpedance AMP, Active HPF, phototransistor I decided to change back to a photodiode instead of a phototransistor since I have used one for a similar experiment in the ...
0
votes
2answers
212 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 ...
0
votes
0answers
109 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 ...
0
votes
1answer
1k views

Problem with high-pass filter - signal gets shifted down

I have a problem where I am passing pulses received from a photo-diode into a high pass RC filter. Circuit shown below. The pulses are being received at 25Khz. Before the filter, the pulses are ...
0
votes
2answers
121 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 ...
0
votes
1answer
166 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 ...