yeah I said it. NG Saabs are like cheap rental cars inside... everything about them inside looks cheap.BLAST! That is what they were missing!
Thanks for that. Very correct. This is what I meant when I said above I was being taught electronics 101 on another forum. I decided to wire them parallel as you suggest after this conversation:When wiring the led, the short wire is the cathode (negative) and long is the anode. If you hook them up backward they will not work.
You also want them in parallel. Each led will drop 0.7v across it in series. If you wire them in series they will work as long as there only a couple. In parallel you always maintain the correct voltage drop to get them to operate. All depends on the voltage spec of the diode you bought.
My responsenorman lovie said:B2 you do need to do a wee bit of no's
Summary = fit only one resistor in the common feed before you split to parallel - use a 2watt power resistor - and better to use say 0 to 500ohm variable resistor pot
2 = size of resistor needed will be less - the more bulbs you wire up ( if you want to keep the same brightness )
3 = what is the voltage drop for the LED's you have ? -( check on packet - think you said 3 volts ?)
4 = what is the recommended current for your LED's ? - milliamps! - example - 30 millamp = 0.03
5= how many lamps are you fitting ?
6=what is the power supply volts ?
(6 minus 3) divided by ( 4 times 5) = how big a resistor you,ll need - - and the value needed will get smaller the more lights you fit - - you can stick with the resistor you have! but the brightness will drop as you fit more bulbs .
however!!!!! - even better - do the sum above - and you have a Resistor range ( size for x 1 LED and the smaller size needed for multiple LED) = get a variable resistor pot that covers this range +/- - hayho you have variable brightness for your dash
Note: - you may have to do another wee sum - what is the power rating of your resistor ? - -- you'll need one that can handle around 2 watt's +/-
Watt's = Supply volts times ( no. LED fitted X milliamps of the LED)
And the instructor confirming the pupils mathematicsB202NUT said:12v main power source
20mA to run LED
5 LED in 1 parallel circuit
2 LED in end circuit
PER YOUR INSTRUCTION THE FIST EQUATION:
12v - 3v = 9v
PER SECOND FORMULA
Each LED requires 20mA
0.02 x 5 LEDs = (X) ohms ÷ 9v = 90 ohm resistor
0.02 × 2 LEDs = (X) ohms ÷9v = 225 ohm resistor
My math seems off..
Thanks for the help!
The resistors pictured are 400 ohm 1/4 watt I believe. So now I understand that parallel wiring is best I gotta go back and get smaller resister with more wattage.norman lovie said:works for me - and a 1 watt resistor will work - but i'd fit say 2 Watt ones - cost diffrence is nothing
Not using the dimmer for the LEDs. Gunna run this on it's own circuit and fuse it for safety.the LED retrofit is actully a pretty cool idea, how does the dimmer work with the LEDs installed, in my experince they tend to be an on/off device, with very little adjust-ability
Numbers, jealousy is a female trait :th_thumbsdownsmileySo quick question, can you even close the top on your vert with that massive ego of yours?