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Hello! (and a little assistance please)

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New Member
Hi there,

My name is Bruce and I am a budding electronics hobbyist.
I am currently building and lighting a plastic model kit which uses blinkers, strobes and static lights, but there is one circuit I am trying to figure out which has me stumped.
This circuit allows for fading of a high intensity blue LED using a capacitor and a switch.
I have wired up everything using a 47uf 25v capacitor, switch and a resistor (the resistor is blue with a 1 x red band at each end and three black bands in between) but I think I may have the polarities mixed up.
Here's what I am talking about;

This is an image of the circuit I am trying to build.
First attempt with this made the LED go very bright until it made a pretty little 'ping' and died, so I changed the resistor value and now the LED simply goes on and off.
Would any of you knowledgeable folk be able to assist please?

Thanks and I hope this has all made sense...


Super Moderator
Most Helpful Member
A bit more information is needed.

Do you want the LED to slowly change brightness from OFF to ON, or ON to OFF, or both ways?

What is the power supply for this? What voltage?

The original resistor sounds like 200 ohm, what is the new value you are using?

The answers to these questions will help us to find a solution for you.



New Member
Hi Jim,

Thanks so much for your response, I really appreciate it...

I would like the LED to fade slowly both ways at the flick of the switch.
The power source is a 9v battery and I'm using the resistor (I think it's 200 ohm) that the sales assistant sold me for the rating of the LED.

Thanks again,

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