Skip to content

Static Circuits

LED Noodle Polarity

Two AA or AAA Battery Power

This simple circuit has just two AA or AA batteries. Each has a voltage of 1.5 volts. When they are configured in series, the voltages of each battery is added together to give a voltage of 3 volts. This is exactly the recommended voltage for the LED Noodle!

./simple-2-battery-circuit.png

Connect the terminals directly to the battery pack. Make sure that the positive polarity is connected to the end with the hole. We used a soldering iron and standard tin-lead solder with a low melting point and that did not impact any of our LED noodles.

Three AA or AAA Battery Power

If we need a little longer battery power, we can upgrade from two batteries to three. This gives us a combined voltage of 4.5 volts (3 x 1.5 volts).

To limit the current, we will need a a 15 ohm current-limiting resistor in series with a battery pack.

three-battery-circuit.png

It is possible to use slightly different values of the current-limiting resistor. A 10-ohm resistor will give a brighter light, but will drain the batteries faster.

LED Noodle Calculator

9-Volt Battery

Although they are not commonly used in our labs, in a pinch you can also use a 9-volt battery to light up the LED noodles.

Use a 100 ohm resistor in series with the battery.

9-volt batteries are easy to connect but they don't offer the best value compared to AA batteries.

USB Battery Packs

One great option is to use a rechargeable USB battery pack. These supply 5 volts and because they are rechargeable, they can be used many times over and over.

In the diagram above, we used a 20 ohm resistor in series with the LED noodle to limit the current to about 62 milliamps. This is more than bright enough for most applications. A 50 ohm resistor is also a good option and the battery will last considerably longer, but the LED will not be as bright.