replace LED with relay that activates large LED panel

Started by Fernando Cassia in sci.electronics.design4 years ago 6 replies
LED

Hi there, I have a circuit that, under some circumstances, lights a LED. The problem is that the LED is too small and can only be seen while...

Hi there, I have a circuit that, under some circumstances, lights a LED. The problem is that the LED is too small and can only be seen while in clos= e proximity of the circuit. What I'd like to do, is keep the LED in place, but add some additional circ= uitry after the LED so the original LED keeps functioning, but when it dete= cts the led has voltage applied to it, drive a relay that ...


sot23-6 LED driver

Started by Jon Kirwan in sci.electronics.design8 years ago 3 replies

I'm looking for an LDO, single LED driver chip in 6-lead SOT23 form for a blue Cree LED (C405MB290-S0100, for example.) I'd like the following...

I'm looking for an LDO, single LED driver chip in 6-lead SOT23 form for a blue Cree LED (C405MB290-S0100, for example.) I'd like the following pins: GND, +5, +LED, -LED, current control V (0 to 3.3V is all I have to work with here), OFF. I've got two rails, +3.3 and +5. Small, cheap, and SMT on one side of the board is what I'm looking for. I need at least 4.1V LED compliance at no less...


Issues with LED grid driving

Started by Bobby Joe in sci.electronics.design8 years ago 21 replies

Is anyone familiar with driving large RGB led grids. Such as 32x32 using cascaded LED drivers. Actually my specific grid is 24x19(each point is...

Is anyone familiar with driving large RGB led grids. Such as 32x32 using cascaded LED drivers. Actually my specific grid is 24x19(each point is one led and not an rgb). I have seen 24-ch led drivers along with 16-ch x 8-com(for 128 total led's). Think of the grid as a led matrix display panel as essentially it is what it is. If I use 24-ch drivers then it requires 19 IC's. Some chips have ...


LED currents?

Started by Jan Panteltje in sci.electronics.design10 years ago 50 replies
LED

I was just soldering a LED in a PIC circuit so I can test some software I am writing. Now I want low brightness, so I derated, 680 Ohm in...

I was just soldering a LED in a PIC circuit so I can test some software I am writing. Now I want low brightness, so I derated, 680 Ohm in series, 5V, 3 V LED drop, green LED. I bought some of the brightest greens ones some time ago... Switched it on, had to close my eyes: 2.9 mA WAY to bright!!! So what do you guys use for LED current these days for a normal non blinding clear transparent...


Looking for post, led drive crt and image

Started by amdx in sci.electronics.design10 years ago 5 replies

Some months ago someone posted an LED driver circuit that ran on 1.5v. It had a very small toroid inductor and a few other parts, it was all...

Some months ago someone posted an LED driver circuit that ran on 1.5v. It had a very small toroid inductor and a few other parts, it was all mounted together with a transistor and led. I seem to recall two images, one with a single led and one with two leds. Anyone have a lead to that post? Mike


Any ideas for driving an array of discrete LED's without running into heat problems?

Started by Anonymous in sci.electronics.design9 years ago 8 replies

I have an interesting problem. I have a display that is roughly a 1.5" diameter circle. I am using an array of discrete SMT LED's (104 of...

I have an interesting problem. I have a display that is roughly a 1.5" diameter circle. I am using an array of discrete SMT LED's (104 of them) to create the display. The LED's are grouped into 4 sets of 26 LED's, each of the 4 sets consists of 4 strings of 4 LED's and 3 strings of 3 LED's. These strings are individually controllable and can be turned on/off in various ways to create dif...


Blinking LED controlling small relay - issues?

Started by xpzzzz in sci.electronics.design5 years ago 6 replies
LED

I have built a circuit that uses a flashing LED (flashing function built- in) to control a relay; the relay resistance is the current-limiter for...

I have built a circuit that uses a flashing LED (flashing function built- in) to control a relay; the relay resistance is the current-limiter for the flashing LED. Do I need to worry about voltage spikes killing the LED, and if so, is there a simple way to prevent that. LED 5V, 12v supply. This works now, but it would be nice to know if it will not break two weeks from now...


Re: Auto Base LED replacements

Started by admiralsmead in sci.electronics.design1 year ago
LED

You could give one of these a...

You could give one of these a try. http://www.aliexpress.com/item/3W-BA15s-LED-Car-Light-Bulb-24V-12V-3014-SMD-LED-BA15s-Lamp-Singl e-Contact-Bayonet/32525056686.html or http://www.aliexpress.com/item/UAU-LED-33-LEDs-LED-DC-12-v-110v-220v-E27-Sinais-de-volta-Reversa -luzes/32499870127.html the trick for LED replacement of a incandescent bulb is to have many SMD LED around the bulb, not just a cou


LED Christmas Light Failures

Started by D from BC in sci.electronics.design9 years ago 21 replies
LED

Are LED Christmas lights really lasting as long as they claim? Anybody witness some failures? I was just on...

Are LED Christmas lights really lasting as long as they claim? Anybody witness some failures? I was just on http://en.wikipedia.org/wiki/Christmas_lights I read stuff like: replacement LED's not available sealed designs preventing LED replacement galvanic corrosion rust coloured plastic lenses fading yellowing of epoxy LED encapsulations D from BC British Columbia Canada


LED luminous intensity in dot matrix displays

Started by markp in sci.electronics.design7 years ago 5 replies
LED

Hi All, I'm currently designing a dot matrix LED display for moving messages. I need some information about what the luminous intensity of a...

Hi All, I'm currently designing a dot matrix LED display for moving messages. I need some information about what the luminous intensity of a multiplexed LED should be for good visibility indoors in a brightly lit room. If I know that I can work out whether I can get away with a 16:1 duty cycle with the 8x8 LED modules I've chosen (80mcd -150mcd per LED at 20mA) and max current of my d...


LED question

Started by Daku in sci.electronics.design6 years ago 3 replies

Could some electronics guru please clarify the following ? An LED is a diode, so the maximum voltage drop through it should be approximately 0.7...

Could some electronics guru please clarify the following ? An LED is a diode, so the maximum voltage drop through it should be approximately 0.7 V. Recently, I was casually going over some LED driver design related Web pages, which stated that typically the LED voltage drop is around 3.3 - 3.5 V ? Could someone please point out how this is possible ? Am I missing something important ?


What does a "self-ballasted" LED mean ?

Started by Anonymous in sci.electronics.design3 years ago 7 replies

Could some electronics guru pleas explain what a "self-ballasted" LED lamp mean ? I have seen LED lamps, running off the AC line, and...

Could some electronics guru pleas explain what a "self-ballasted" LED lamp mean ? I have seen LED lamps, running off the AC line, and powered by a simple small 5V 1 Amp SMPS, but what exactly does a self-ballasted LED lamp mean ?


Component needed?

Started by Photon713 in sci.electronics.design9 years ago 10 replies

I have built a very simple circuit that attaches to a horseshoe pitching glove. It consists of a 9v battery, red led and turns on when two bare...

I have built a very simple circuit that attaches to a horseshoe pitching glove. It consists of a 9v battery, red led and turns on when two bare wires close the circuit when the leads, one on the finger and one on the thumb, cause the led to go off when the shoe is released. I would like to somehow reverse when the led goes on and off. I would like to add a component(s) that causes the led...


Possible High LED current with long life time

Started by Pubs in sci.electronics.design9 years ago 16 replies
LED

Hi, I have a application where my LED currents are switched as in a matrix. My current LED on time is 60 us and off time is 15240 us....

Hi, I have a application where my LED currents are switched as in a matrix. My current LED on time is 60 us and off time is 15240 us. The intensity is problem thus I pump a higher current in that 60 us (applied potential is arround 9V in that period of time ) and that gives the required intensity. LED doee not heat up since LED current duty cyle is extreamly small (rms current is also ...


single switch on off and mode select

Started by panfilero in sci.electronics.design5 years ago 7 replies
LED

Hello, I'm trying to come up with a way to only have one button, and use that to power my circuit on and off, and also to flip through...

Hello, I'm trying to come up with a way to only have one button, and use that to power my circuit on and off, and also to flip through different modes of operation. For example, my circuit is suppose to blink an LED in different patterns, click it once, turns on LED is on click it again LED is blinking slow click it again LED is blinking fast click it again LED is blinking slow (any ...


Correcting a LED response curve?

Started by Jacques St-Pierre in sci.electronics.design9 years ago 61 replies

Hi, I am designing a product using a Vactrol (led controlled resistor) to simulate a RTD. The led intensity will be control by the buffered...

Hi, I am designing a product using a Vactrol (led controlled resistor) to simulate a RTD. The led intensity will be control by the buffered output of a D/A chip. It is working, but to be useful, we have to operate the led in the worst region of it's curve, resulting in very coarse response. Since I do not have enough resolution on this D/A to correct that from software I am searching ...


Digital Ballasts

Started by samaden in sci.electronics.design6 years ago 2 replies
LED

Eclipse LED Digital ballasts provides you with more research and data on LED light technology than the common LED retailer.Digital ballasts...

Eclipse LED Digital ballasts provides you with more research and data on LED light technology than the common LED retailer.Digital ballasts offer LED and HID technology in order to be better equipped when and if you decide that this cost-effective, environmentally conscious technology is right for you.At Eclipse LED, tes


using transistors to switch LED's with floating load buck regulator - problem

Started by CJ in sci.electronics.design8 years ago 1 reply

I have a project I am trying to do where I use a Zetex ZXLD1360 constant current buck regulator to drive either one of two strings of three high...

I have a project I am trying to do where I use a Zetex ZXLD1360 constant current buck regulator to drive either one of two strings of three high power LED's. I have string of blue and a string of red LED's. The output from the reguator is connected to two NPN transistors, which control which string of LED's is turned on (the LED and inductor are connected to the emitters of the transistor...


Feeling red LED light?

Started by Jan Panteltje in sci.electronics.design8 years ago 23 replies
LED

I was yesterday playing with some lithium cells and a red LED. I noticed if I shine that LED on my hand I could feel some warm feeling. But...

I was yesterday playing with some lithium cells and a red LED. I noticed if I shine that LED on my hand I could feel some warm feeling. But sort of dismissed it as imagination... Then I just tried this again, and I am pretty sure I can feel red LED light. Anyone else? No high intensity, 3.4 mA at 10 cm high brightness LED. Long time ago I did read about people who can feel color. Do no...


LED Driver recomendations

Started by James in sci.electronics.design9 years ago 1 reply
LED

Hi all, I am looking for a high power led driver for the following: 3 identical led's in series with a total forward voltage of...

Hi all, I am looking for a high power led driver for the following: 3 identical led's in series with a total forward voltage of 11volts constant current drive 800-1200ma Input source is a 12Vrms AC with > 10Amp drive capability (Can not use a DC supply for this application) Can anyone recommend an led driver or perhaps a manufacture to start with? Thanks, James