Smooth ignition of LEDs

Computer homemade products 106 420 11

Today I am listening to you, I want to present a simple scheme that has no serious practical application, but rather created to please the human eye. The purpose of this circuit is that it ignites the LEDs quite smoothly and slowly, with no threshold jumps as, for example, on Chinese Christmas tree garlands or when using a microcontroller. In fact, here is the diagram itself:

It is assembled from very affordable parts that can be pulled out of old Soviet equipment or, like me, bought. All the parts cost me 18 rubles. I used an smd resistor to reduce the bulk of soldering.

I used this circuit to illuminate the system unit with an LED strip powered by 12V; I took the same 12V from the fan connector on the motherboard. By increasing the capacitance of the capacitor you can increase the “ignition” time LEDs, you can also experiment with the resistance value.
Video of the system in action:

come back

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Comments (11)

#1 Plunya Guests 24 September 2013 14:38
0

Does this system not overheat when used for a long time?
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#2 Maksim Guests 25 September 2013 18:57
0

Every now and then it will overheat. Or it will just boom...
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#3 c.k.-85 Guests January 19, 2014 06:41
0

But how can you use it if it can bang? lighting may be needed for a long period of time.
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#4 ErMaK Guests January 31, 2014 08:35
0

I'll start testing in the evening, I'll start thinking after it goes off!))
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#5 Ilnar Guests 14 February 2014 14:44
0

you can use 2000 microfarat 25 volts
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#6 guest Guests 30 April 2014 20:53
0

yes it might just light up faster
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#7 Humanoid Guests 23 July 2014 23:20
0

Better to use a PWM controller... better energy efficiency and no overheating. Although, it will be more cumbersome and more expensive.
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#8 Edward Guests 19 April 2015 22:26
2

take a more powerful transistor or a field-effect transistor like IRFL3205, they can draw about 40 amperes through themselves. They have low transition resistance when powered LEDs will not heat up at all
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#9 Guest Vadim Guests 26 February 2017 18:59
4

Tell me, I did it according to the diagram! Why does it flare up quickly and go out slowly?
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#10 Guest Alexey Guests 23 May 2018 07:55
1

It would be better to take mje13003 or 13002 or 13009 instead of KT817. I took the last one - it works and does not overheat. I even left it without a radiator)
but KT817 needs to be mounted on a good radiator.5-10 minutes and it’s already hot
- Answer