0
Trying to make some indicators for a bike and am going to use 1.5 volt leds and a 12 volt 11ah battery by putting 8 leds in series was wondering whether resistors are needed not to short the leds?
DJSCD
Resistors will be needed in all cases when driving LEDs from a voltage source, unless you are using LEDs that already have a built in current limiting IC inside the package (a few do these days, for example I have some blinking LEDs that need no resistor they have a blinker IC built in that also limits current).
However you have another problem that you obviously are not aware of. 8 LEDs rated at 1.5V in series totals exactly 12V. But your battery is only rated at 12V. As the battery discharges its voltage slowly drops, the moment it drops under 12V all the LEDs will turn off! I strongly recommend that you use no more than 7 LEDs rated at 1.5V in a circuit powered by a 12V battery, so that the battery can actually gets a chance to discharge beyond its knee voltage. In this case the resistor will drop the remaining voltage, whatever it is depending on the charge state of your battery.
Wiki User
∙ 10y ago
Add your answer:
Earn +20 pts
Will putting another resistorin parallel raise or lower the total resistors in circuit?
Placing another resistor in parallel to an existing resistor will lower the total resistance in the circuit. RParallel = 1 / Summationi=1toN (1 / Ri)
Will 1000 mah charger damage 500 mah battery?
probably, yes. imagine putting twice a much AA's in your radio or whatever.
What does an ammeter measure?
amps 'an electrical measure of current.'An ammeter is an instrument used to measure current (amperes), you dont measure ammeters!YEAH
How much voltage does a battery produce?
Depends on the battery but they are current sources as opposed to voltage sources Standard AA, AAA, C and D batteries all give 1.5 volts each, but rechargeable NiMH batteries are often 1.2 or 1.25 volts.
What do you call the process of putting things together?
Assembly would be a name for putting things together.
How do you prepare indicators frum plants?
by getting its petals and putting it to fire......
Can you ruin a car battery by putting it on a battery charger everyday?
Yes
Why do you not get 14 volts when running but the battery never dies?
Your putting a charge on the battery when its running.
How do keyboards translate digital information?
by putting a battery
Does more power flow into a battery than out of it?
No. That would defy the point of putting the battery there in the first place.
How can you refurbish a car battery?
There is no fool proof way. Get a new battery if putting it on a slow charger does not work.
Does the auto door lock keypad work with a dead battery?
No. It does not require very much power. If the battery is not putting out enough power to turn the starter, but is putting out some power it may still work. If the battery is totally dead it will not work.
Can you drain a battery by putting it in the refrigerator?
No unless you leave it in there for months. Want to drain it, the connect something to the battery and leave it on.
How do you unfreeze a Pantech matrix?
try turning it off then removing the battery then putting the battery back in the turning it on. it worked on mine
Is it true that putting cassette tapes in the freezer revitalises them?
No, putting cassette tapes in the freezer will not revitalize them. This will damage the tapes. However, putting batteries into the freezer will revitalize the battery charge.
How can you tell what damage was done by putting in car battery backwards?
Car battery charges can check the damage done to the actual battery but to the entire car is another story
Brand new battery won't stay charged in my 1998 cadillac?
The battery is bad or the alternator is not putting out the correct voltage and is bad.
