Hi all,
I am currently working on a project in which I am required to construct a 555 timer circuit that makes an LED flash on/off in 1-2 second periods. This circuit is powered by taking a 240AC with 2 12v secondary windings and converting it to 15-16V DC by using a full wave rectifier.
So far, I have managed to construct both of these circuits. The result I am being given is an LED that stays on when it is supposed to flash. The breakdown of the components used in this project is:
555 Timer Circuit:
R1 (value of 1K)
R2 (value of 330K)
R3 (value of 1K)
Capacitor C1 (value of 4.7 microfarads)
555 Timer
LED
Apologies in advance for the rather poor diagram/plan:
Following calculations made using CircuitDigest`s astable 555 timer LED flasher calculator, the R1 and R2 values of 1 and 330K respectively and the C1 value of 4.7uF were shown to give an on/off period of 1.04 seconds (within required range). However I am getting a constant ON from the LED. I have so far replaced the 555 pin 3 times and replaced the capacitor twice and ensured the polarity was correct. The DC rectifier circuit has also been run through an oscilloscope (as seen below).
(testing the 555 circuit using an independent power supply)
If my rectifier circuit is also giving the same result as the power supply, would I be right in saying that it is functioning correctly? The rectifier circuit does not include smoothing but from research appears to work just fine for this project.
Thanks for your input in advance.
I am currently working on a project in which I am required to construct a 555 timer circuit that makes an LED flash on/off in 1-2 second periods. This circuit is powered by taking a 240AC with 2 12v secondary windings and converting it to 15-16V DC by using a full wave rectifier.
So far, I have managed to construct both of these circuits. The result I am being given is an LED that stays on when it is supposed to flash. The breakdown of the components used in this project is:
555 Timer Circuit:
R1 (value of 1K)
R2 (value of 330K)
R3 (value of 1K)
Capacitor C1 (value of 4.7 microfarads)
555 Timer
LED
Apologies in advance for the rather poor diagram/plan:
Following calculations made using CircuitDigest`s astable 555 timer LED flasher calculator, the R1 and R2 values of 1 and 330K respectively and the C1 value of 4.7uF were shown to give an on/off period of 1.04 seconds (within required range). However I am getting a constant ON from the LED. I have so far replaced the 555 pin 3 times and replaced the capacitor twice and ensured the polarity was correct. The DC rectifier circuit has also been run through an oscilloscope (as seen below).
(testing the 555 circuit using an independent power supply)
If my rectifier circuit is also giving the same result as the power supply, would I be right in saying that it is functioning correctly? The rectifier circuit does not include smoothing but from research appears to work just fine for this project.
Thanks for your input in advance.