See… this is exactly why you don’t post a circuit that needs to be altered, without explaining the changes needed in detail.

To use the circuit in post #8 you must…

Lower the voltage to the 555
Raise the power of the transistor and adjust the base resistor accordingly.

A MOSFET can be used to replace the transistor, but the choice must be made very carefully.

Actually I would advise using a MOSFET because the base current needed to saturate a power transistor @ 2 amps would be at the 555s limit.

You could use a Darlington instead of a MOSFET, but you need to consider the extra voltage drop across the CE junction, this might require a heat sink, and could reduce the LED brightness.

 

i tried #8 and #10. in #8 i changed the resistor value and in place of 2222A transistor i have taken MOSFET

OK, and what happened? What supply voltage were you using for the 555?

One way to diagnose this circuit is to slow down the 555 to 20Hz or less, so that you can see it flash if it is oscillating. You can use a single small LED and omit the MOSFET switch until you can verify that the 555 is operating. Then add the MOSFET and the larger LED, then finally raise the 555 frequency again at the end, once the circuit is working.

 

See… this is exactly why you don’t post a circuit that needs to be altered, without explaining the changes needed in detail.

To use the circuit in post #8 you must…

Lower the voltage to the 555
Raise the power of the transistor and adjust the base resistor accordingly.

A MOSFET can be used to replace the transistor, but the choice must be made very carefully.

Actually I would advise using a MOSFET because the base current needed to saturate a power transistor @ 2 amps would be at the 555s limit.

You could use a Darlington instead of a MOSFET, but you need to consider the extra voltage drop across the CE junction, this might require a heat sink, and could reduce the LED brightness.

Can you provide the schematic what you are telling?

 

OK, and what happened? What supply voltage were you using for the 555?

One way to diagnose this circuit is to slow down the 555 to 20Hz or less, so that you can see it flash if it is oscillating. You can use a single small LED and omit the MOSFET switch until you can verify that the 555 is operating. Then add the MOSFET and the larger LED, then finally raise the 555 frequency again at the end, once the circuit is working.

I am using below uploaded circuit. in that circuit changes i made is in place of controller i used POT. (2) 24V voltage i gave to 7815 regulator in attached file voltage mentioned is 54 V but giving only 24V. when iam using this circuit LED output is not coming after running for some 5hrs and there is no physical damage in the circuit

 

I am using below uploaded circuit. in that circuit changes i made is in place of controller i used POT. (2) 24V voltage i gave to 7815 regulator in attached file voltage mentioned is 54 V but giving only 24V. when iam using this circuit LED output is not coming after running for some 5hrs and there is no physical damage in the circuit

Some suggest the 24V DC to 15V or 12V DC regulator other than 78** series