Ok, so i'm doing a little project with my younger brother and i need to know will a 1.5v (AA) battery destroy two LED's, which each have a maximum forward voltage of 2.5v and a maximum forward current of 40ma, when wired in a series circuit along with a 1.5 volt moter.
would this work, would there be too much or not enough power?
Thanks.
2007-12-17 07:06:10 · 4 answers · asked by Rover 3 in Science & Mathematics ➔ Engineering
Sorry, i ment to write motor.
2007-12-17 07:35:59 · update #1
No you won't destroy the LEDs with a single 1.5V battery. In fact you won't light the LEDs at all if they are connected in series, and you might not even light up a single LED (especially if they are yellow or green LEDs).
In order to light 2 LEDs and run a motor will probably require 2 batteries in series (3 volts total).
If you have red LEDs it may be possible to get some light out of them by connecting them in parallel with a single 1.5 V battery. They will draw the current they need, but there may not be enough forward voltage to turn them on.
With 3 volts, you can light up 1 LED for sure, but you'd need a resistor to prevent the LED from getting too much power. The motor in series with 1 LED will act as a resistor, and the circuit will probably work OK. If you really want to light up 2 LEDs and run a motor (in series), I would try 3 AA batteries (4.5 volts).
.
2007-12-17 07:50:13 · answer #1 · answered by tlbs101 7 · 0⤊ 0⤋
Firstly, if you have a volt meter, you can only wire it in parallel, otherwise you'll get next to no current at all.
In reality, you probably have a MULTIMETER. That is, it when you set it to the current measurement mode, you can wire it in series with the led. In current measurement mode the resistance of the meter is negligable.
Now, the LED with have a forward voltage drop of 0.5 to 0.7 volts, so your 1.5V battery will have no problem lighting the LED.
If you were to use a true 1.5V power supply, you could very well destroy the LED since you have no series resistor to limit current.
However, batteries have much higher internal resistance than a real power supply, so even if you used a fresh alkaline battery, you'd still have trouble burning out the LED.
2007-12-17 15:25:40 · answer #2 · answered by Anonymous · 0⤊ 2⤋
Check to see how much current the motor draws. It wouldn't be too hard to exceed 40 mA.
2007-12-17 15:18:36 · answer #3 · answered by flyin520 3 · 0⤊ 0⤋
go to this link .it's very simple.http://ourworld.compuserve.com/homepages/Bill_Bowden/led.htm
2007-12-17 16:03:30 · answer #4 · answered by Mahdi M 1 · 0⤊ 0⤋