unknown circuit for led flasher

what about if i will not using the pcR606 how can drive 5 leds in series with this COB??

hi,
I suggest to put the load (the leds) always in the collector of the tranzistor . Emitter following connections will not saturate the led's with the mcu

You didn't use a current limiting resistor for leds. Maybe your leds are already dead.

If the COB is producing SCR trigger pulses, and based on the PC606 being used, that's almost certainly what it does, you will have to drive a monstable circuit from each output and use the monostable output to drive the transistors. To be honest, without a specification or an oscilloscope to analyze the COB output, it is almost impossible to help you. a COB is not a specific device, it's a technology to mount silicon directly on a PCB to reduce packaging costs, what is actually in the silicon is anyones guess. Do you even know what the supply voltage requirements of the COB are?

Brian.

you can take a part of my stroboscopic rotational speed meter posted on https://www.edaboard.com/threads/262525/
I used 5 white leds (there are drawn only 4)

you can adjust the flashing frequency from a single potentiometer

the supply voltage requirements of the COB is 5volts

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thank ypu for reply Zsolt1 but i need a simple and not expencive circuit like that to drive 4leds because microcontroller is very expensive

COB output drives only one led. You need to give +12V or +15V to collector of transistor like 2N2222A and put a resistor in series with the 5 leds to limit Ic to 10 or 15 mA. As COB is able to drive single led it will be sourcing or sinking 10 - 20 mA. Put a resistor to limit this current to 5 mA which will be the base current for the transistor.

hi,
sorry for confusing you :lol: , you do not need the microcontroler . In that aplication i used the microcontroler to measure the frequency, compute rpm & display the result on LCD screen. The oscilator made by NAND gate driving>npn tranzistor>LED's is all you need. I used 2 gates from the circuit CD74HCT132 (it has 4 souch gates in it). The first gate is an oscilator and te second gate is a kind of buffer stage to drive the npn tranzistor. I added that buffer to avoid any influence of the output stage to the oscilator ().
I draw a separate circuit containing only the relevant part for you
**broken link removed**
with a little modification . Instead of using the LM7805 stabilizer cip to get the 5 V supply for the cd74hct(hc)132 cip , the circuit uses a parallel voltage regulator made with the 5 V zener diode and 220 ohm rezistor

PS: the main supply for the circuit is 15 V. If you want to go lower with the supply voltage you need to rearrange the led's in a series/parallel mixture . For example you can supply all from 5 V, no need for zenner diode and rezistor and the pin 14 goes directly to +5V , also all the led's go in parallel each with adequate series rezistor.

I actually have something similar, it's in an LED chaser using a COB and PCR606 SCRs. A small box that sequences 5 strings of LEDs with a control that sets the sequence speed. If it's the same as mine, the LEDs run on an AC supply from a 'wall wart' mains adapter which produces 24V. The rectification is carried out by the SCRs and they are triggered by pulses from the COB. It is a very crude system and doesn't even have current limiting in the LEDs which probably accounts for several going faulty. If it's like mine, no amount of transistor current boosting will help and I would guess (never bothered to trace a schematic) it also needs a reference input to sense the AC phase.

To be honest, it would be more expensive and much more work to get this thing operational than to start afresh with a small micro.

Brian.

yes its the same circuit like yours and its used for led chaser please if you can send me the shematics because i like to made something like that for my message board
thank you again for your attention

why you don't program your own Led chaser
here's a led chaser that a created with assembler:

I would advise you to do something like Kgavionics has shown. You can make it simpler by using a micro with a built in clock generator so the crystal isn't needed. I never bothered to trace a schematic for the one I have, it is so dedicated to one purpose that I don't consider it useful for anything else. If you want to get yours working, the easiest way is to refit the PCR606 SCRs again and build it like it used to be.

How do you see it working as a message board? Is is nothing more than a sequential pulse generator.

Brian.

i don't like to use microcontroller all that i want is to drive leds with the circuit that i posted before

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i like this circuit because we can blink leds without microcontroller
and i like to realize the circuit that you had Betwixt

What if the COB itself is a micro-controller?

if it is a microcontroller i will programme it in mikroC compiler
what i want is to build a sa me circuit like that i posted before

You make get such COB's from China.

how can i get it??

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i need reference??

so, you don't need a simple flasher....

try this

thank you for teying to help me but the complete circuit that i need is a transformless power supply + led flasher with COB that i posted before with transistr CPR600 to flash 10 led for each transistor