This is where i measured the voltages from...i guess i'm not sure what you mean by measuring 'across' the resistor then?? I assumed the 5.36 value here is measuring across the resistor :? ...sorry i'm a noob, can you tell **broken link removed**
This is where i measured the voltages from...i guess i'm not sure what you mean by measuring 'across' the resistor then?? I assumed the 5.36 value here is measuring across the resistor :? ...sorry i'm a noob, can you tell **broken link removed**
It means one meter probe at each end of the resistor, so you measure the voltage actually dropped across the resistor. The same with the LED's, place one meter probe at either side of an LED to measure it's voltage drop.
All circuits in the datasheet show a capacitor on the output of the regulator to keep it from oscillating if your wiring isn't perfect. Use a ceramic disc capacitor.
i mean as compared to the schematics on the previous page....there is another capacitor in there the other didnt have (0.1uF)...is this necessary for this to work properly...or can i just simply changed the resistors
...will do....need to do a little more shoppin for parts, hopefully i can hit the electronics place after work tomorrow before they close. Thanks again.
I see 10 LEDs but the circuit has only 2. What did you do? Make a bunch of these circuits?
I would take the two green LEDs with their 120 ohm current-limiting resistor, connect them to my variable voltage supply then turn down the voltage until they were off. Then I would set the circuit's minimum voltage to be a little less.
You can reduce the value of the 620 ohm resistor like this:
I see 10 LEDs but the circuit has only 2. What did you do? Make a bunch of these circuits?
each color is on a seperate dimmer...they are wired in parallel series of 2leds
I would take the two green LEDs with their 120 ohm current-limiting resistor, connect them to my variable voltage supply then turn down the voltage until they were off. Then I would set the circuit's minimum voltage to be a little less.
I'm not sure what you mean by "connect them to my variable voltage supply" ?? I have them hooked up as shown in the schematic...just the greens ones dont dim off when the dimmer is at its minimum
You can reduce the value of the 620 ohm resistor like this:
Yes, change the resistor until the LEDs are dimmed enough.
Are you connecting LEDs in parallel? You shouldn't because then they would have different brighness levels as your display shows. Also, with LEDs in parallel then they share the current and are half as bright as they should be. Do it this way:
Yes, change the resistor until the LEDs are dimmed enough.
Are you connecting LEDs in parallel? You shouldn't because then they would have different brighness levels as your display shows. Also, with LEDs in parallel then they share the current and are half as bright as they should be. Do it this way:
yes...that is how i have them...sorry maybe i'm using the wrong phrasing when i said paralleled series....is that not what this arrangement would be called? But yes its strange that these ones behave this way...some are brighter than others...only on the green leds are doing this...the white and oranges are fine...all the same brightness. :?
yup the 560 resistors did the trick...not sure why why the green leds have variation in brightness??...oh well...i can live with it..its only when they are very dim.
Here's a shot of the guts, need to tidy up the wiring a bit on the inside, slap the etched glass on front and back, then she's a done deal...woohoo!!
Thanks again for all the help...much appreciated. Final assembled pics to follow soon....
Nice going, its done! :lol:
Some of the green LEDs were made on a warm Friday afternoon and the others were made on a freezing Monday morning. They are all different, unless you purchase "batched" ones from Agilent at Digikey. :lol: