Help creating a series of 2 LEDs

In summary, the participant is trying to light two LED lights using a battery pack that contains 4 AA batteries and a 100 ohm resistor. He has hit a snag and is unsure of why the batteries started to smoke. If he could get help from someone who is more knowledgeable about electrical engineering, he would be grateful.
  • #1
Hi, electrical engineering has always interested me and recently I have been trying to trying pick it up as a hobby by doing simple soldering exercises. While everything has gone smooth so far, I have hit a snag with the current little project I have been working on.

So my goal is to light 2 LED lights (which I believe is 1.9-2V @20mA) using a battery pack that contains 4 AA batteries (should be 6V) and a 100 ohm resistor. The tricky part for me is that I want to be able to switch these lights on and off using one 5A 125VAC SPDT switch (toggle).

I've tried many LED series calculators to try and find the right configuration and just when I thought I did something went wrong. What I had was, the 2 lights soldered together by wire in which one end had the positive leg and the other negative (is that always called ground?). The positive side continues to the resistor, and this is where I had to improvise. The toggle has 3 prongs, and I believe the two on the outside corresponds to the binary position of the toggle, so I connected the resistor to one of the ones on the outside. I then soldered he middle prong with the positive wire coming out of the battery pack with the 4 batteries. The prong furthest from the first that is connected to the resistor, received the negative wire coming from the battery pack as well as the negative end of the LEDs legs.

When I flipped the switch the lights finally glowed with much trial and error, but I did not celebrate for long because after 10 seconds I saw the pack containing the batteries begin to smoke, so I cut the power. So that leads me here. I know exactly what it means when an LED glows brilliantly then suddenly fizzles out, however I did not foresee the batteries smoking.

If you all have any idea why that would be or what I should do to correct my project, I would really appreciate it! I apologize for what is probably a very simple problem, I would just love to learn from this experience and continue perusing this amazing craft. Thank you so much!
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  • #2
Your switch has 3 terminals, but you only need the center one and one of the outside ones. Leave the other terminal alone.

If you don't already have a multimeter, now might be a good time to get one.
You can get a digital multimeter for around $10 and it will save you having to guess a lot of the time.

1. How do I connect the LEDs to a power source?

You can connect the LEDs to a power source by using a breadboard or a solderless breadboard. You will need to use resistors to limit the amount of current going through the LEDs to prevent them from burning out. You can refer to online tutorials or ask for help from someone with experience in circuit building.

2. How do I determine the appropriate resistor value for my LEDs?

The appropriate resistor value for your LEDs can be determined by using Ohm's law. You will need to know the voltage and current rating of your LEDs and the voltage of your power source. You can then use the formula V=IR to calculate the resistance needed. You can also use online calculators or consult with a professional for assistance.

3. Can I control the brightness of the LEDs?

Yes, you can control the brightness of the LEDs by using a potentiometer or a variable resistor in your circuit. This will allow you to adjust the amount of current going through the LEDs and therefore control their brightness. You can also use a microcontroller or a PWM signal to dim the LEDs.

4. How can I make the LEDs blink or create patterns?

You can make the LEDs blink or create patterns by using a microcontroller or a timer circuit. This will allow you to program the on and off times of the LEDs and create different patterns and effects. You can also use various coding languages, such as Arduino, to control the LEDs and create more complex patterns.

5. What safety precautions should I take when working with LEDs?

When working with LEDs, it is important to use the correct resistor values to prevent them from overheating and potentially causing a fire. You should also avoid touching the LEDs while they are connected to a power source to prevent electric shocks. It is recommended to wear safety glasses and work in a well-ventilated area when soldering the LEDs. Make sure to also follow any safety guidelines provided by the manufacturer of the LEDs.

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