Technical LEDs!
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LEDs!
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Re: resistors!
oh your going to get hurt for this thread....
oh your going to get hurt for this thread....
Re: resistors!
dont worry bulldog he doesn't mean the temp sensor replacement with a resistor trick, he's asking about how to wire up a LED in a 12v DC circuit. you'll destroy an LED if its connected directly to the 12v supply so you have to add a ressitor on the positive wire to reduce the current. if you buy LEDs that are designed to be plugged into an existing bulb holder then there is no need but if you go to an electrical supply store and buy LEDs they are way cheaper but you need to add the resistor. cant remember what value resistor is best so ask at any electrcial supply store. they only cost a few pence each so you could just buy a few. more resistance will make the LED dimmer, not enough will destroy it. heres a quick wiring diagram i've done for you
dont worry bulldog he doesn't mean the temp sensor replacement with a resistor trick, he's asking about how to wire up a LED in a 12v DC circuit. you'll destroy an LED if its connected directly to the 12v supply so you have to add a ressitor on the positive wire to reduce the current. if you buy LEDs that are designed to be plugged into an existing bulb holder then there is no need but if you go to an electrical supply store and buy LEDs they are way cheaper but you need to add the resistor. cant remember what value resistor is best so ask at any electrcial supply store. they only cost a few pence each so you could just buy a few. more resistance will make the LED dimmer, not enough will destroy it. heres a quick wiring diagram i've done for you
Re: resistors!
and to avoid the next question here's the diagram for connecting several LEDs in series (like xmas tree lights) you only need one resistor for as many LEDs as you like in series
and to avoid the next question here's the diagram for connecting several LEDs in series (like xmas tree lights) you only need one resistor for as many LEDs as you like in series
Re: resistors!
you can avoid the resistor issues by buying LEDs from here:
http://www.m-99.co.uk/Car_Neon_LED_Lighting/car_neon_led_lighting.html
m99 is cheapest on net. they sell all sorts for all sorts its great
you can avoid the resistor issues by buying LEDs from here:
http://www.m-99.co.uk/Car_Neon_LED_Lighting/car_neon_led_lighting.html
m99 is cheapest on net. they sell all sorts for all sorts its great
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Re: resistors!
oh, fhew, carry on
jug said:
oh, fhew, carry on
Re: resistors!
They still don't make pink sidelights Would it be chavvy to go for the colour change option inside and out for show/ cruise purposes? I haven't seen very many about so can only conclude that it's cceptable.
jug said:
They still don't make pink sidelights
Would it be chavvy to go for the colour change option inside and out for show/ cruise purposes? I haven't seen very many about so can only conclude that it's cceptable.
EI4GGB
Member
Re: resistors!
To calculate the correct value of series resistor for an LED, there are 3 things you need to know - the forward voltage and current of the LED, and the supply voltage you will be using. most LED's are designed for a forward current (denoted If in the technical specifications) of about 20 milliamps, or 0.02 Amps, but check to make sure. some will work with lower current just as well. Then the forward voltage Vf is usually around 1.2 volts for RED leds, rising to approx 3 volts for WHITE leds. The supply voltage will need to be greater than the forward voltage, or it won't light. This will not usually be an issue with a single LED and a car battery voltage (12V), but will be if you put several LED's in series. so you could use approx 10 red leds in series (10 X 1.2V = 12V), but only 4 WHITE leds (4 X 3V = 12V).
To calculate the value of resistor needed in OHMS, take the supply voltage (12V usually, but in a car with engine running this may rise up to 14V), and subtract the forward voltage Vf, or if using several LEDs in series, subtract the sum of the forward voltages of the LEDs. Then using ohms law, divide by the forward current required in AMPS (20 mA = 0.02 Amps). this is the value in ohms. not all values are available easily, to take the next highest standard value available (e.g. calculatated 310 ohms, next highest standard value = 330 ohms)
summary :
resistor value ohms = (Vs (supply voltage) - Vf (Sum of LED forward voltages)) / If (foward current in Amps)
example :
resistor value ohms = (14V - 12V (4 x WHITE LED Vf)) / 0.02 A = 100 ohms.
If the resistor gets hot, its probably too small, so use the next higher power rating available, e.g. 0.5 or 1 Watt.
To calculate the correct value of series resistor for an LED, there are 3 things you need to know - the forward voltage and current of the LED, and the supply voltage you will be using. most LED's are designed for a forward current (denoted If in the technical specifications) of about 20 milliamps, or 0.02 Amps, but check to make sure. some will work with lower current just as well. Then the forward voltage Vf is usually around 1.2 volts for RED leds, rising to approx 3 volts for WHITE leds. The supply voltage will need to be greater than the forward voltage, or it won't light. This will not usually be an issue with a single LED and a car battery voltage (12V), but will be if you put several LED's in series. so you could use approx 10 red leds in series (10 X 1.2V = 12V), but only 4 WHITE leds (4 X 3V = 12V).
To calculate the value of resistor needed in OHMS, take the supply voltage (12V usually, but in a car with engine running this may rise up to 14V), and subtract the forward voltage Vf, or if using several LEDs in series, subtract the sum of the forward voltages of the LEDs. Then using ohms law, divide by the forward current required in AMPS (20 mA = 0.02 Amps). this is the value in ohms. not all values are available easily, to take the next highest standard value available (e.g. calculatated 310 ohms, next highest standard value = 330 ohms)
summary :
resistor value ohms = (Vs (supply voltage) - Vf (Sum of LED forward voltages)) / If (foward current in Amps)
example :
resistor value ohms = (14V - 12V (4 x WHITE LED Vf)) / 0.02 A = 100 ohms.
If the resistor gets hot, its probably too small, so use the next higher power rating available, e.g. 0.5 or 1 Watt.
Re: resistors!
no need for the head scratching
http://www.metku.net/index.html?path=mods/ledcalc/index_eng
no need for the head scratching
http://www.metku.net/index.html?path=mods/ledcalc/index_eng
EI4GGB
Member
Re: resistors!
Bloody internet and calculators . No wonder kids cant add 2 and 2 anymore...
Bloody internet and calculators
. No wonder kids cant add 2 and 2 anymore...Re: resistors!
Lots of lovely information, mmm, perhaps some more mods on the way, as my rear boot light isnt working so can see a self made replacment coming along.
Lots of lovely information, mmm, perhaps some more mods on the way, as my rear boot light isnt working so can see a self made replacment coming along.
Re: LEDs! willenhall westmids
they have a wicked rang of leds in hear im going there sat to pick some up and some letters in chomealike are 45p
http://hootys.co.uk/ECOM:.php
they have a wicked rang of leds in hear im going there sat to pick some up and some letters in chomealike are 45p http://hootys.co.uk/ECOM:.php
Re: LEDs! willenhall westmids
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http://www.m-99.co.uk/ is a great place for LEDs and other boyracer bits, even bodykits.
Dark Ranger
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Im sure this is the wrong place to ask but is there any guide as to how to get in to my dashboard to replace the led's?? and the same goe's for the controle's under the radio(heat,fan)?
i think there is a guide on fiatboo.co.uk but i cant remember to be honest.
a haynes manual would be a good start.
a haynes manual would be a good start.
They're not ordinary 3 or 5mm LED's they're called SMD LED's or something, and a real bitch to replace since they're surface mounted on a PCB.
It's probably advisable to practice on a spare instrument cluster from a scrappy.
Correct figure for a single LED in series with a resistor on a 12V supply is 390Ohms btw.
It's probably advisable to practice on a spare instrument cluster from a scrappy.
Correct figure for a single LED in series with a resistor on a 12V supply is 390Ohms btw.
