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Suggest me a LED flashing circuit

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Member level 3
Nov 30, 2009
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Hi All,

I am looking LED flashing circuit, in first time switch press LED blink and second time switch press LED glow continuous.


Re: LED flashing circuit

Third push of the switch the LED goes off? You need a counter chip, to count the number of pushes of the button. Its outputs then either fire up the blink circuit or the glow circuit or the off circuit.

Re: LED flashing circuit

no third push again LED blink. I do not want to use any IC. Any transistor or opamp based ckt?

Re: LED flashing circuit

I assume you dont have microcontroller on your borad.
you need a simple toggle circuit which can generate a 0V or 5V based in pressed switch. Then you need a clock cicuit to generate a low frequency pulse to make LED blink. Now to select between blink and constant ON you can use a SPDT switch with inputs to be (5V & bufferred clock) and samling input to be the output of toggle circuit. If you have a diffculty finiding a toggle circuit then I can share some of them with you. it will be simple transistor based.


Re: LED flashing circuit

yes, I am not using any Micro-controller in my board. This type of circuit basically i want to use in my mic preamp ckt.
When MIC is mute LED blink and MIC is in use LED continuous glow.
Any opamp based LED toggle ckt is appreciated.

Re: LED flashing circuit

I do not want to use any IC. Any transistor or opamp based ckt?
OP are mosly ICs as well. With transistors, you can calculate at least 2 for an on-off FF, 2 for a steady/blink FF and 2 for a pulse generator.

Re: LED flashing circuit

You can try with 555 timer
1) Configure the 555 timer in Astable mode.
2) Connect the switch between vcc and pin4. connect the resistor of 10k between pin4 to gnd.
3) Now LED in negative logic... i.e cathode goes to pin3 and anode goes to Vcc.

When mute switch is not pressed, pin3 goes low, LED glows.
When switch is pressed, oscillation begins LED starts blinking.
Hope this helps...

do you want to toggle the led with a switch??? press 1st time led is continuously ON press again it goes OFF, press once again and its on Again ?

or do you want to make blinking go on and off ???

try reading this link , may be it helps

press 1st time led is blink press again it goes continuous ON, press once again blink and its on Again.

You can construct Oscillator for Flashing LED using NAND gates, R,C components. Then use SPDT type of push button to switch between oscillator and +5V for flashing and continuous LED glow respectively!

If other than cheapest possible way is there, then share here!

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