What type of resistor should i use

This is shown in the diagram top right. We can therefore write this as:. For example an ultra bright blue LED with a 9V battery has a forward voltage of 3. We have added a great tool to the Kitronik website that takes the strain out of calculating the current limit resistor.

Simply select which LED you are using from a drop down list. Enter the battery voltage and it will tell you what resistor to use. It even tells you what the colour bands will be on the resistor. Click here to visit the calculator page. Learn more about the author read more ». In this tutorial you will learn about the formula that connects these three values, see some examples and answer some questions to test your understanding. Hi Henry. The formula in this case does give you 0 Ohms.

Should i use the 8V in the calculator to revise this set up? Hi all, complete novice trying to learn,purchased a kit from bitsbox with breadboard, thought id start out really simple but stumped already, Set up the simplest circuit 9v battery ohm resistor and red led, it was bright for a second or 2 then dimmed quickly, could smell the led burning. I used several online calculators to get the resistor value all said the same.

Used the rule of red led 2v. So want to learn yet so frustrated already. Thanks, tried ohm direct to led and to battery with out breadboard and works great, maybe i have a problem with the breadboard, Enthusiasm in full flow again now thanks very much. Hi there, i am running 10 leds from a 9v transformer … After using a calculator it has told me to use a 33ohm resistor.

I will be running a parralel circuit. Does each led require a resistor, or can I just use the one 33ohm resistor for the whole circuit? In theory you could use a single resistor for your LEDs but then you would have to calculate for the total current going through all LEDs. That would have you running them all off a 3. You should be able to run 10 white or blue LEDs as 5 pairs 5 parallel strings of 2 in series with a much smaller level of power wastage.

If they are orange, yellow or red you could probably have them in threes. One ohm resistor is in series with another resistor and a 20V battery. I am a complete newb to all this, but I wanted to wire up 2 white 3mm leds to a 12v molex from a computer power source in series.

So my question are: 1. I noticed you mentioned that you upped the 20ma for forward current to hit a middle mark between 20ma and 30ma so would you in this case aim for a middle mark of 35 for mine being 20ma to 50ma peek?

Does it matter what size resistor you use as long as it is over the amount you need? Meaning if you only need say ohm resistor could I hypothetically use a ohm resistor and not have a problem with lighting the leds or do you need to get a resistor that is as close as possible to what you need because the resistor would then start drawing all the power and the leds would be left with out power?

Last question side question I was also interested in putting in some RGB led tape that has a remote receiver into the same computer. The Led tape claims to only use 12v to run, now if I wanted to do away with the led tapes power block and somehow wire a molex plug powering from the computer power block to the remote receiver for the tape which has a female dc plug input only would you have any ideas on how one might do that?

Thank you in advance for any help you can give me. You need to use a resistor of the right resistance for your application, that is also rated for AT LEAST as much power as will be generated.

However, the higher it is above the minimum, the dimmer the LED will run. See answer 3. Not sure; check with the manufacturer. Thank you very much for reply. I was questioning though for a little clerification my leds as stated above seams to have a continuos current of 20ma but a peak of 50ma so what would you advise i should aim for? Thank you again for any help. The problem is that there are many correct ways to connect them together. If anyone could help me I would really appreciate it.

Thank you in advance for any info you can give me. I am a total newb. Here is my problem. Would be any damage to LED? Is it better to use a 32v transformer with only mA? Any help will be highly appreciated. Not relevant. I have asked a clear question and I I need a clear answer or nothing. What if I tell you that I am not a newb anymore. I have read a lot in the mean time, I have tested my rig and I have done lots of measurements. Are you going to give me a different answer.

Or maybe you have no answer but you have plenty of time on your hands…. The datasheet should also include information on how to drive them. Want to run one LED off a 1. Trying to find a coil small or a iC chip to increase the power out put to around 5 volts to run the LED.

Can you help? Hey this was really helpful. I have a question though. I need to run about 25 LEDs in a parallel circuit. Do you take the Amp produce by the baterries in to the calculation? How do you apply the fomular to this? Please advise, thanks Thank you. Your explanation is very clear. Actually, I am a telecommunication person and doing electronic stuff as a hobby too like the first person who posted this thread. My intention is change the light bulbs in my car to pure white LEDs.

Similar to the website I have attached. For more on op-amps, click here for my Instructables. The timer is one of the oldest and most widely used ICs on the market. Set up as an astable multivibrator, or oscillator, the output is a square waveform and the duty cycle and period are fully adjustable according to the value you choose for your resistors and capacitors.

For a basic tutorial on the timer, click here for my Instructable. As mentioned, there are too many uses for resistors to cover them all here.

Hopefully this has has clarified the question, if only so far as to say that it really depends on what you want the resistor to do. Getting a good simulator like Multisim will greatly benefit you as well since you can change things simply and easily and then monitor every possible output parameter in real time.

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