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LED fade in/fade out

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1-3-2-4

Member
I was thinking about something what about using a relay instead of the switch? i flip the wall switch on which powers the 12V adapter which turns the relay on.. then when time to turn off the relay should turn off as well, right? I'd should still get fade out without having to flip the switch on the device it's self?
 

alec_t

Well-Known Member
Most Helpful Member
A relay won't help. If you turn the wall switch off then there's no power to keep the LEDs alight, so they can't fade out :(
 

1-3-2-4

Member
crap.. reason why I asked is while I'm gone I wanted to make sure they see knew how to turn on the light.

Also the CD40106BE I have the connections is it the same as all other Hex schmitt triggers?
 
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alec_t

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the CD40106BE I have the connections is it the same as all other Hex schmitt triggers?
I don't know. It's the same as the 7414, if that's any help. Check the datasheets.
 

roabish

New Member
Hi Guys, can I toss a spanner in the works, can you make this work for a 220v lamp and have the fade in and fade out variable (POT) and in a constant cycle? I need to do that for my son's project....any help please.

Thanks
 

alec_t

Well-Known Member
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@colin55
I agree about the supply voltage, but the OP was asking if the connections were the same.
 

alec_t

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can you make this work for a 220v lamp and have the fade in and fade out variable (POT) and in a constant cycle?
Not with the circuit posted in this thread. That would require a completely different design, especially if (as I'm guessing) the 220V lamp is to be run from AC mains. I suggest you start a different thread and provide more detail of your requirements.
 

1-3-2-4

Member
I ended up heading back out to buy a switch I picked up a small push button switch and a project box and the 0.1 uF cap i forgot to pick up with the rest of the parts.

I "think" I have the resistors since I picked up a bunch a few weeks ago but they are all mixed so I'd have to check
 

1-3-2-4

Member
Moving so slow on this since work and people are pulling me away.. I'm looking in my bag of resistors and the only one I may have issues with because I don't have are R2 and R3.. however for R3 is that 8k2? the closest I have for R2 is 69k which is going to require 3 resistors
 

alec_t

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1-3-2-4

Member
Hmm something is not right.. since I'm using the irf510 I have the source to (+) and (-) to drain and u1d to gate.

on the switch I'm seeing like 8v with the button up

the gate is only getting about 5V

gotta be something with the way the resistors are connected
 
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jimy245

New Member
Getting-an-LED-to-fade-on-and-off
 

audioguru

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The first inverter of the Schmitt-trigger inverter IC is the oscillator. It causes the LEDs to turn on, turn off, turn on etc. You can make an oscillator wirh a couple of transistors if you want.

The link you posted has an error. I corrected it here: **broken link removed**
It does not have an oscillator, it uses a manual switch instead.
 

audioguru

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nope still not right I'm only seeing like 5V on the gate I will have to see if I have time tonight to check it out
Doesn't the circuit use a +12V supply?
The outputs of the CD40106 is 0V to +12V.
The gate is driven from+0.7V to +11.3V so the average is about +6V. Maybe that is what your meter shows.
 

1-3-2-4

Member
yes uses a +12V supply

the leg of the wiper and pot are connected together, no?

I just got back home and have to be at work at 4 am so I wont be able to get much done tonight, I still think it's something with the resistors since I ended up putting like 4 parallel to get near target resistance.
 

1-3-2-4

Member
I think it's U1b and U1c the connection to the pin is after and not between the resistors just to be sure I'm going to bring out the o-scope.

meanwhile I lost a hard drive last night :mad:
 
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