Questions tagged [photoresistor]
A photoresistor or light-dependent resistor (LDR) or photocell is a light-controlled variable resistor.
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Solar Array Control With Photocell
We did search on this topic before making this post, but this is as close as we found; Link to question from 2020: Solar Panel-Photocell Wiring
... which didn't seem to be closely enough related to ...
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LED light bulb is flickering when switched on
I am a Physics Major student and have to do a project in our end sem.
Since we read a lot of theory and workings and very less practicals, I am a bit weak in electronics.
So here is the problem.
Our ...
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How to bright up LED when it's dark without wasting battery energy?
I am trying to design night light LED that brights up when it's dark. I know a solution using transistor that "drains" current so LED has not enough to light up.
A current flow through ...
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Shadow-triggered LED fade circuit
I'm making an interactive art project and I'd like to have an LED that turns on when someone puts their hand in front of a light sensor (photoresistor). I got that working. Next step is that I'd like ...
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How to prevent photoresistor sensor from draining battery
I'm looking for a simple hack to minimise current when detecting change in light intensity using photoresistor.
I'm using ATTiny85 in deep sleep (power down, ADC disabled, using below 1 microamp) ...
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Tuning photoresistor circuit with resistors
I've done small circuits for a long time, although nothing more than a few basic ones. I am now trying to control an IO-signal to Raspberry Pi. Since Raspberry Pi doesn't have analog pins, I came ...
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How to test photo interrupters
I have come upon two photo interrupters in a calibration kit circuit. The circuit seems to not respond. How can I check these photo interrupters? The green LED is responding when an object is brought ...
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Ltspice: vary resistor
I wanted to simulate an LDR and a specific case where I have a bright LED using PWM.
This is the schematic:
I was changing the resistor as stated here which comes from a previous discussion ...
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Solving for closed loop current in photoresistor-transistor circuit
I am working on trying to relearn some basic circuit analysis and I am stuck on the attached problem. I have a circuit using a transistor and photoresistor to turn on an LED when dark. I have ...
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Why will this circuit only work if it is assembled live?
Updated Schematic picture. Some components (power supply, other things connected to the MOSFET) are omitted. The ICSP header was kept since I think it may be interfering somehow.
I have an ATTiny84 ...
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How to choose a phototransistor or photodiode?
I've found a photoresistor (yes, resistor, probably 30 years
old) in my scrap box, attached it to an ATtiny as ambient light
sensor, with a 100kΩ resistor as voltage divider towards +5V.
On power on, ...
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In this circuit, the light intensity sensor (LDR) only senses 3_2 cm. How can I improve the sensitivity of this sensor to reach 1m?
In this circuit, the light intensity sensor (LDR) only senses 3_2 cm. How can I improve the sensitivity of this sensor to reach 1m?
https://ibb.co/c3X1NRS
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What is the mathematical relationship between the resistance of an LDR and light intensity in lux?
I have been surfing the internet and my physics books for the relationship between the resistance of an LDR and light intensity (a formula), and so far I have found nothing.
If any of you have a ...
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More current in non-inverter comparator hysteresis using a photoresistor
I'm doing a small circuit where I need automatic LED's to turn ON in a low light environment. So I decided to use a photoresistor (more light less resistance) connected to a non-inverter hysteresis ...
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Two different LDR circuits: what's the fundamental difference?
Here’s what’s going on. I’m working on a programmable light timer (of course I could use something like Alexa, but I’d rather go for the challenge and build something to my own design), where the LDR ...
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