All Questions
Tagged with schematics led
36 questions
5
votes
8
answers
2k
views
Circuit that turns two LEDs off/on depending on switch
I have been trying to solve this for the last couple of days and no matter what I do, green LED always receives some current.
What I would like to happen is when the switch is closed, turn on just the ...
- 153
1
vote
1
answer
73
views
Circuit schema 2 ways WS2812 connect with 1 PCB layout
Hey all I am having a difficut time trying to figure out how to go about the following:
I am wanting to just make 1 pcb but I am using WS2812B LEDs and therefore needs to be in the correct direction.
...
- 805
4
votes
2
answers
323
views
LED "optical noise" when powered by DC
I am currently designing a circuit where:
An LED driven by a constant current driver shines directly into a photodiode. (I have also tried without the op amp constant current circuit.)
The photodiode ...
- 43
0
votes
0
answers
450
views
Designing A Flickering LEDs Circuit
I'm currently designing a simple circuit for to fire 4 LEDs in such a way that they appear to flicker. I want each to appear appear to fire randomly and independent of one another. I wanted to ...
0
votes
0
answers
254
views
WS2812 LEDs with ESP32-schemantic
I have a WS2812 LED module I want to interface with an ESP32. I want to use a button and a sensor to control the LEDs.
I am not sure if the schematic is OK. Do I need a resistor for the LEDs, and if ...
0
votes
2
answers
67
views
Review my layout to see if I've missed anything
This is my first attempt at a schematic to Vero layout so a more educated and experienced set of eyes would be much appreciated. I am also open to suggestions and criticisms.
Also, I'm putting this in ...
- 1
0
votes
2
answers
171
views
Understanding part of TI AN-1839 LED Dimming Schematic
I'm trying to evaluate LED drivers for a project I am working on, and I came across this reference design for the TI LM3402/04: https://www.ti.com/lit/ug/snva342e/snva342e.pdf. The design employs a ...
- 362
1
vote
1
answer
307
views
Is it possible to individually control each LED the way this schematic is designed?
I'm currently researching a design which includes the below schematic :
This is supposed to be an array of LEDs which are attached to the front panel of the device for indicator lights.
However, I am ...
- 209
0
votes
1
answer
334
views
Picking transistor and base resistor to dim LED using PWM
I'm working on a project where I need to dim a 30 cm LED strip. I'm using a STM32 pin to drive the base of a NPN BJT-transistor. The pin is can source a maximum of 25mA. The LED strip consists of 12 ...
0
votes
3
answers
188
views
Trying to understand schematics of a microcontroller (TM4C123GXL)
I have a TM4C123GXL microcontroller with a hwllo-world app. that makes some LEDs to blink.
I have done this 'hello-world' by following a tutorial, but now I want ...
- 1,395
0
votes
4
answers
55
views
Estimating current when voltage drops > voltage input
Let's say I have a circuit with a 5V battery and a 2V LED and a 100 ohm resistor. Ignoring certain properties of an LED, I can estimate the current by doing:
...
- 679
1
vote
2
answers
84
views
Solving for current with voltage drops
Given the following circuit:
Why is the current through the circuit 34.7mA instead of 35 mA? My thinking was that:
The LED draws two volts, so it effectively makes the battery 7V instead of 9V.
...
- 679
17
votes
1
answer
2k
views
What are the various 'properties' of a diode?
I have come across various properties of a diode, phrased differently in different places (product sheet, everycircuit, etc.). For example:
The wavelength is the simplest and that is the color of ...
- 679
2
votes
2
answers
135
views
Small electronic project kit
I ordered this electronics project kit which consists of a small PCB. You have to solder the components onto the board.
The components are:
Two 510 ohm resistors (green, brown, brown)
Two 33k ohm ...
- 500
1
vote
1
answer
96
views
Review of my LED spinner Schematic
After a few months of questions and modifications to my design. I have what I believe to be a LED Spinner that can change the speed of the spinning LED. Before I send this design off to get printed on ...
- 157
0
votes
1
answer
198
views
Connecting an IC to LEDs - would I use a transistor?
I have this breadboard circuit, which is basically a 65C02 CPU that has 16 Address pins. I want to wire these up to LEDs. Below, I've connected them directly, which is likely all kinds of bad (Too ...
- 1,319
0
votes
1
answer
2k
views
How to drive 2/3 color LED's and circuit schematic
I need to use 2 or 3 color LED for my circuit.(preferably 3 color one). I am going to use PIC18F26K83 to control the LED. However, I am confused how am I going to make it change colour. I think I ...
2
votes
1
answer
200
views
Calculating the resistance for the base of a transistor
I'm building a circuit for my little niece's birthday (I'm already overdue with a couple of days).
I started building it before I well understood enough about transistors and no I'm running a little ...
- 125
-2
votes
1
answer
144
views
Schematics: If I turn off light in room 1 the light in room 2 turns on and vice versa?
I need something like this:
If I turn off light in room 1 the light in room 2 will turn on and vice versa (if I turn off light in room 2 the light in room 1 will turn on). Also I don't know how can I ...
- 103
2
votes
1
answer
424
views
LM3466 circuit symbols, SEN/SRC to ground?
I'm reading the LM3466 datasheet (page 9) and am confused about the symbol downstream of the SEN/SRC pins and R(sen). Is this a ground symbol? If so, why do they use multiple different ground symbols ...
- 45
1
vote
0
answers
132
views
Schematic review for simple LED circuit?
I'm pretty new to circuit design, I am trying to make a small board with a few LEDS that uses a toggle to turn on and another toggle to either show the LEDS always on or to blink the LEDS. I believe ...
- 251
0
votes
0
answers
306
views
Few questions on my project (Schematics) -> resistor, transistor
I have a school project where I have an electronic circuit connected to a microprocessor, with a thermometer controlling LEDs, and buttons changing the date, etc.
I made a quick schematics (orange ...
- 161
1
vote
2
answers
508
views
Why will my led not light up & why does my input voltage fluctuate when I add a wire?
This design is suppose to light up the LED When the sensor is under light, and turn off the LED when the sensor is covered.
I noticed two problems:
My LED won't light up.
When I measure the voltage ...
- 27
4
votes
1
answer
788
views
How to separate the schematic of a RGB LED into 3 individual LEDs in Altium?
I'm designing a RGB LED matrix with the following footprint:
Which has the following schematic:
It's just a combination of three LEDs in one component. In my matrix design, I need to wire the ...
- 143
5
votes
8
answers
1k
views
Lighting either of two LEDs, or none, based on digital input
I ran into a problem which I tought was extremely simple, and after giving it some thought for more than 2 hours I had to recognise it actually is quite complicated. The problem is the following:
I ...
- 378
9
votes
4
answers
2k
views
Minimum energy required for LED blink to be visible
I have a 5V schematic with 15n capacitor and I wondering if I will be able to blink an LED, powered from this capacitor. My calculations is that the capacitor will have about 0.2 uJ of energy. This I ...
- 3,032
0
votes
1
answer
1k
views
Schematic Check for Color Organ
I am making a small color organ just for proof of concept fun. I am using 3 passive low, band, and high pass filters with their outputs connected to an envelope detector and a BJT that drives each LED....
- 199
0
votes
1
answer
158
views
Questions About Schematic
I am working on a color organ and want to use a design similar to this.
I understand the gist of the schematic, but I have a few questions about it and how it works.
First: I understand that it is ...
- 199
0
votes
2
answers
98
views
How would I create this kind of circuit?
I'm just starting out with electronics, this should explain why my "schematic" is so readable.
I'll attach it and explain further.
I know how to create a simple circuit with the main slide switch and ...
- 1
0
votes
3
answers
544
views
grounded emitter or common collector circuit or something else?
first of all, I'm sorry if I did not use the technical correct symbols for the circuit diagram, but I think it will do.
I've multiple questions. Maybe someone can give me a hint.
I'd like to control ...
0
votes
1
answer
87
views
20VDC LED Illumination
I'm looking to build a simple test circuit, where I can get an LED to illuminate when it senses 20VDC or above, and to remain off if it is sensing any less.
2
votes
1
answer
329
views
How do I connect this piece of electronics to show the digit display? (from satellite decoder)
I have the following piece of board/electronics:
Link: https://i.sstatic.net/pNErb.jpg
Link: http://i.imgur.com/4BCKU21.jpg
Now, I recently bought an arduino, so I want to connect the digit display ...
- 381
1
vote
2
answers
408
views
What does this symbols means on the LCD pin outs?
I am trying to understand this product : NHD-C0220BIZ-FS(RGB)-FBW-3VM
It is a LCD with back light in reg, green, blue (not clear for me if they are mixed or you can only choose one)
What do you ...
- 933
0
votes
2
answers
1k
views
Circuit with a main switch that powers on/off 4 different switches with LEDs
I've been searching for a circuit that has a centralized switch, with 4 different switches for separate groups of LEDs.. and all I get for a result are diagrams without a centralized switch.
Well, to ...
1
vote
3
answers
3k
views
Are the LED's in this diagram Backwards
I'm trying out a Make Project: Sound-O-Light Speakers
It has this diagram:
The LED's are backwards in this diagram, right? The "arrow" (anode) part of the LED should be hooked up to the positive (+) ...
- 749
12
votes
1
answer
5k
views
What transistor do I need to drive many LEDs and how should I hook it up?
I know that a transistor amplifies a signal, but I've never used one. I have this design here and I want to add 15 LEDs connected to each pin, instead of 1.
How I could incorporate a transistor to ...
- 593