I have an LED bulb mounted in my speedometer to warn when the long range tank is running low.
Recently noticed it wasn't coming on so whipped the light out to check it and can see no obvious signs of it being broken. Does anyone have a way of testing an LED bulb to see if it hasnt burnt out? If not the bulb then how can I test the tank 'sender'? (its a lamby fast flow tap which came prewired)
Cheers
Tommy
Testing an LED Bulb?
you will need a 12v feed to test but led only work in one direction , the tap will need to be removed and a circuit tester used to determine that it is switching correctly
Its in bits scooter club: www.facebook.com/groups/132415046859320
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Tommy Boy
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Thanks... I found this on the web:
Testing an LED
Never connect an LED directly to a battery or power supply!
It will be destroyed almost instantly because too much current will pass through and burn it out.
LEDs must have a resistor in series to limit the current to a safe value, for quick testing purposes a 1k resistor is suitable for most LEDs if your supply voltage is 12V or less. Remember to connect the LED the correct way round!
For an accurate value please see Calculating an LED resistor value below.
Calculating an LED resistor value
An LED must have a resistor connected in series to limit the current through the LED, otherwise it will burn out almost instantly.
The resistor value, R is given by:
R = (VS - VL) / I
VS = supply voltage
VL = LED voltage (usually 2V, but 4V for blue and white LEDs)
I = LED current (e.g. 10mA = 0.01A, or 20mA = 0.02A)
Make sure the LED current you choose is less than the maximum permitted and convert the current to amps (A) so the calculation will give the resistor value in ohms ().
To convert mA to A divide the current in mA by 1000 because 1mA = 0.001A.
If the calculated value is not available choose the nearest standard resistor value which is greater, so that the current will be a little less than you chose. In fact you may wish to choose a greater resistor value to reduce the current (to increase battery life for example) but this will make the LED less bright.
Was hoping someone on here had a tried and tested method in plain english as algebra was the death of me at scool!!
Testing an LED
Never connect an LED directly to a battery or power supply!
It will be destroyed almost instantly because too much current will pass through and burn it out.
LEDs must have a resistor in series to limit the current to a safe value, for quick testing purposes a 1k resistor is suitable for most LEDs if your supply voltage is 12V or less. Remember to connect the LED the correct way round!
For an accurate value please see Calculating an LED resistor value below.
Calculating an LED resistor value
An LED must have a resistor connected in series to limit the current through the LED, otherwise it will burn out almost instantly.
The resistor value, R is given by:
R = (VS - VL) / I
VS = supply voltage
VL = LED voltage (usually 2V, but 4V for blue and white LEDs)
I = LED current (e.g. 10mA = 0.01A, or 20mA = 0.02A)
Make sure the LED current you choose is less than the maximum permitted and convert the current to amps (A) so the calculation will give the resistor value in ohms ().
To convert mA to A divide the current in mA by 1000 because 1mA = 0.001A.
If the calculated value is not available choose the nearest standard resistor value which is greater, so that the current will be a little less than you chose. In fact you may wish to choose a greater resistor value to reduce the current (to increase battery life for example) but this will make the LED less bright.
Was hoping someone on here had a tried and tested method in plain english as algebra was the death of me at scool!!
M.D.M.A. Scooter Collective
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wack 63
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From experience I would say the fault will be in the tap.I have LEDs wired directly to my dip and high beam wires and no external resistors are used http://www.maplin.co.uk/5mm-12v-leds-35 ... lWin111003 .Try a new LED first.
Connected directly to a battery and burnt out...this could be the answer to my rev counter which WAS backlit but now isn't...wired direct to a battery.