Tagged Questions
-1
votes
1answer
67 views
How involved is tapping power from a device to add LED's?
I am thinking about doing a little hobby project (if it proves to be not so difficult) and I am not exactly sure where to start. Macintosh computers have an illuminated Apple logo, and there is a ...
2
votes
3answers
163 views
Checking materials (cheapest possible) to be used for a solar dark-detecting LED light bulb circuit
I want to make this circuit, which includes a joule thief:
It's for a solar dark-detecting LED light; and I'm trying to follow this guide: ...
1
vote
2answers
260 views
Help verify 8x8x8 LED cube circuit
I am a beginning hobbyist when it comes to electronics. I have read lots of theory but I only have a little bit of hands on experience. I would like to build an 8x8x8 LED cube and I came up with this ...
6
votes
3answers
383 views
How to drive a 20mA LED From a 4mA max GPIO Pin
I have an IC that has an GPIO with which I would like to drive a LED.
Since the device will be running off battery, keeping the power use low (Zero maybe) while the LED is off as a priority.
The ...
3
votes
3answers
224 views
Parallel and Series Circuits Question (Electron Flow)
So this is a pretty basic question, I understand the aspects of parallel and series circuits but don't understand why?
For instance:
How can the Battery be "drained" faster when say 3 LEDS are ...
-2
votes
1answer
114 views
Current amplifier concept in solar panel [closed]
Whether the output of the solar panel is given to a current amplifier to increase the ampere rating? So that we can increase the ampere hour rating of the battery which will be connected to the solar ...
1
vote
3answers
252 views
Simplest circuit for making Christmas lights flash
I bought a Christmas LED light yesterday but it is static. I don't know much about electronic circuits but I learned something in college on RC circuits. I am wondering if we can build a flasher with ...
1
vote
1answer
116 views
How does an LED connect in a circuit?
So, I know (conventional) current goes from the + pole of the battery into the anode of the LED, leaving through the cathode and into the - pole of the battery.
However, I read the cathode is the ...
0
votes
2answers
498 views
Connecting 5 12V LEDs in a parallel circuit
I recently bought 5 12V ultra bright LEDs (all identical), and want to hook them up to a battery pack of 8 AA batteries. So I figured I could just make five parallel circuits with one LED in each, and ...
-2
votes
1answer
255 views
LED circuit with 17 parallel diodes
I have a parallel LED circuit with with 17 red LEDs. I am using a 555 and microcontroller with a 9V alkaline battery (500mAh).
In chasing mode, 3 red LEDs go continuously from right to left, so ...
5
votes
1answer
183 views
Wiring different CREE LEDs together
I would like to create a light source consisting of 6 CREE XP LEDs:
4x XP-E Red - 2.3V @ 700mA Datasheet
1x XP-E White - 3.5V @ 1000mA (Datasheet is the same as above)
1x XP-C Royal Blue - 3.5V @ ...
2
votes
4answers
358 views
What are some methods to achieve constant LED brightness over large temperature ranges?
I would like to regulate the light flux output of an LED or laser diode over its entire operating temperature range by varying the current.
What are some different methods to achieve this?
Edit: ...
0
votes
3answers
2k views
How to know how many LEDs can be used at a given voltage
I am newbie to electronics. Basically I developed a mini circuit just to understand concept of electronic circuit. What I did was I developed a circuit with 3Volt AA battery and 1 LED. The LED lighted ...
2
votes
4answers
1k views
LED Voltage Drop in Series
Perhaps a Simple Question, but maybe Im misunderstanding "Voltage" drop in terms of LEDS.
So I have a Circuit wired up with a 9V Battery, one 270ohm Resistor and 3 Blue LEDS (that draw around....20ma ...
5
votes
1answer
176 views
Why doesn't this work? (Simple Circuit)
Honestly this is almost embarrassing to ask, but I might as well suck it up and ask why (even though it's probably obvious)
Assuming I plug in that 9V battery into the +/- connections, the LED will ...
4
votes
4answers
542 views
How to hack a walkie-talkie to light up LEDs when it receives a signal
Rookie circuit-bending question: I am trying to hack a walkie-talkie to light up some LEDs when it receives a signal. I figured the easiest thing to do would be to have the LEDs light in relation to ...
1
vote
2answers
185 views
Thevenin Resistance?
I don't understand our professor's explanation for the answer to this problem:
An LED is connected in series to a 150ohms pull up resistor and a MOSFET with drain-source resistance of 3ohms. The Pull ...
0
votes
1answer
94 views
Leveraging DC series circuit to power higher voltage LED panel
I have a IKEA RGB Dioder set where each channel requires 12Vdc (& 1.25W), I want to connect this to my Phidget LED 64 Advanced.
Each channel on the Phidget can provide a maximum of 5Vdc with ...
1
vote
2answers
2k views
Connecting LEDs to a 9V battery
1) I have 6 4.5V 20mA LEDs and have connected them to a common 9V battery. Doing this I made 3 parallel circuits with 2 LEDs in each.
Now, I see that most pages that describe LED circuitry say that ...
0
votes
3answers
369 views
How to wire up a circuit with a button that cancels other circuits
What I really want to do is slightly more complex than this but I can distill it down to the following concept. Let's say I have 4 buttons and 4 LED lights. Each button turns on 1 LED light. If any ...
