Hello need some help with timer and 24v

Thread Starter

rastaman46

Joined Nov 17, 2011
75
Hello need some help with timer and 24v

Im got 100 leds in parallel its based on 24v MAX:8VA

Im inserted new ultra bright leds and they works but im try switch it on 12v true ne555 to make them flashing and im end with 4 leds on.

How to do to make all 100leds flashing true timer ???
 

Thread Starter

rastaman46

Joined Nov 17, 2011
75
circuit use



Instead of 100k im use 1k
instead of c1 1UF im use 1000uf (make it flash nice slow)
no switch in it

but rest is the same
 

SgtWookie

Joined Jul 17, 2007
22,220
Since you are not using the switch, you don't need R1/R2.
That means you can leave R3 at 100k, and just increase C1 to 10uF; you will use less power that way, and the timing will be the same.

Here, have a look at the attached. I've added a 12v regulator with input and output caps, and a power MOSFET to turn the LEDs on and off. The 2N3904 has a limited current sink capacity; perhaps 100mA if you have 10mA flowing through the base. A power MOSFET is a voltage controlled device; it is being used as a switch here. The MOSFET shown can sink several amperes worth of current.

I just threw some LEDs wired in strings with resistors to give you the general idea how that would work. The number of LEDs you can use in series and the resistor you will need will depend on the specifications of the LEDs that you are using.
 

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Thread Starter

rastaman46

Joined Nov 17, 2011
75
Hi thanks for circuit.

Got my parts delivered all works nice thanks for that.

Any chance to do like 3 options on circuit "Fast-slower-very slow" say intervals is 30-40 seconds?
 

SgtWookie

Joined Jul 17, 2007
22,220
You're getting about 1-1/2 seconds now, right?

If you replace C3 with a 220uF capacitor, you'll get about a 35 second interval.

Alternatively, you could replace C3 with a 100uF cap, and R1 with a 220k Ohm resistor to get roughly 35 seconds.
 

SgtWookie

Joined Jul 17, 2007
22,220
You didn't mention what flash rates you wanted besides the 35 to 40 second rate.

If you want it to be easily adjustable, try replacing C3 with a 100uF capacitor, and replace R1 with a 200k pot in series with a 22k resistor.
 

Thread Starter

rastaman46

Joined Nov 17, 2011
75
im playing with C3 just for speed now im got 1uf on its flash quick 10uf bit slower 47uf more slower as bigger its its at slower it works dont you? .

But im want to make it flash quick for 30s than flash slower for 30s that back to fast flash again.

if you know what im meant (circuit change its speed it self every 30s or so)
 

SgtWookie

Joined Jul 17, 2007
22,220
Oh, I see - well in that case, you will need another timer circuit just like the 1st one (U1, C3, R1, M1) - but for this new part of the circuit, you will need to change C3 to 100uF, R1 to 430k Ohms. That will give you about 30 seconds on, and 30 seconds off.

M1 will then connect the ground of an additional capacitor that is connected in parallel to the original C1.

Have a look at the attached. The green trace is the output of the left 555 timer; ~30 seconds high, ~30 seconds low.
The cyan trace is the output of the right-hand 555 timer, showing the flash rate.
 

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Thread Starter

rastaman46

Joined Nov 17, 2011
75
Thanks for your big help

but now im got problem im test circuit on DC adapter witch was 21V

im plugged old adapter back and circuit dont work because adapter is AC/AC.

Did any chance to get it working on that AC/AC adapter or i need DC one?
 

SgtWookie

Joined Jul 17, 2007
22,220
Thanks for your big help

but now im got problem im test circuit on DC adapter witch was 21V
You said it was 24v? :confused:

im plugged old adapter back and circuit dont work because adapter is AC/AC.

Did any chance to get it working on that AC/AC adapter or i need DC one?
The circuit requires DC in order to function. You may have damaged or destroyed it by connecting it to AC.
 

Thread Starter

rastaman46

Joined Nov 17, 2011
75
You said it was 24v? :confused:





The circuit requires DC in order to function. You may have damaged or destroyed it by connecting it to AC.
Im test it on 21v one problem im had was half lights was not on (once im done and test circuit im try on my old adopter just for 2sec or so did not work )

Than im spouted what my old adapter is AC

No circuit works if its on DC but dont work on AC

sorry for my bad skills
 

SgtWookie

Joined Jul 17, 2007
22,220
I edited what you wrote, into what I believe that you meant to write.
If I made an error in my corrections, please tell me where I am not correct.

I tested it on 21v (DC). One problem that I had was half of the lights were not on.
If you built the circuit like the 2nd schematic I posted, then the LED strings that are not lit either have one or more bad LEDs in the string, or the connections are poorly made, or one or more of the LEDs are installed backwards. The anode must be towards +21v, and the cathode must be towards the 21v return (-21v).

Once I built and tested the circuit on 21V DC, I tried it on my old adapter just for 2sec or so did not work

Then I spotted that my old adapter is AC

Now, the circuit works if its on DC, but does not work on AC
The circuit was not designed to work on AC. You would have to add a bridge rectifier, filter capacitors, and a regulator in order to be able to use AC input from a transformer. It is cheaper and easier to just get a "wall wart" plug-type DC power supply.
 
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