Making a Blinking LED 555 Timer

In summary: Thanks for the help!In summary, the person is trying to create a LED that phases on and off for 1 second. They are using a Timer 556 and hooked it up in a way that made sense from the 555 IC timer wikipedia webpage. They created a schematic, but were wondering whether someone would mind checking it.
  • #1
trustnoone
17
0
Hi guys, I figured I might try making a LED to phase on and off for around 1 second, to be perfectly honest I have NO idea what I'm doing really. But figured that's the best way to learn right :P. So I'm using a Timer 556 and connected it in a way that kind of made sense from the 555 IC timer wikipedia webpage. I created a schematic, but was wondering whether someone would mind checking it? is it right? is it wrong? is there any method to my madness, or am I just being silly connecting random stuff together haha. It will be very much appreciated,

I haven't looked into too many other circuits (read: I didn't use search to find someone elses thread) of the same type as I'm trying to go about it more by myself then just copying someone else's circuit, I know that makes it easier to learn but I find I learn better when I just kinda try things :P. But yeah cheers!


Schem_Blink.jpg
 
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  • #2
I know nothing, but pin 1 should be ground, pin8 is VCC +4.5-15V, I know there's a load of ways to hook them up, I don't know
 
  • #3
LordVader88 said:
I know nothing, but pin 1 should be ground, pin8 is VCC +4.5-15V, I know there's a load of ways to hook them up, I don't know
Really? I'm a bit confused about the pins especially the trigger :(, I did notice there was heaps of ways to hook them up as well. I'm hoping what I want is a monostable timer, just to give the impression of being high for 1 second then low for 1 second. I'm also putting VCC to 5V so hopefully its enough, it seems to be in your range that you stated :D
 
  • #4
Since your trigger pin is connected directly to ground( Trigger pin is the Negative terminal input to the comparator whose positive terminal is at Vcc/3 Volts, so In this comparator the positive terminal is always greater than the negative terminal so this comparator output is always 1 , this is connected to S terminal of rs flip flop whose o/p is IC output ...so you 'll get high output always...so your LED will always be on I guess.
 

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  • #5
reddvoid said:
Since your trigger pin is connected directly to ground( Trigger pin is the Negative terminal input to the comparator whose positive terminal is at Vcc/3 Volts, so In this comparator the positive terminal is always greater than the negative terminal so this comparator output is always 1 , this is connected to S terminal of rs flip flop whose o/p is IC output ...so you 'll get high output always...so your LED will always be on I guess.
Oh right, that makes sense, I was confused with the trigger part as I didn't really understand it too much from the wiki page. Would that mean i should connect it to VCC? I just saw your schematic now, is that the inside of a 555 timer? Since it looks really interesting, I've seen a bit about how flipflops work, so I might try going over mine again using the logic from your schematic.
Cheers
 
  • #6
trustnoone said:
Would that mean i should connect it to VCC? I just saw your schematic now, is that the inside of a 555 timer? Since it looks really interesting, I've seen a bit about how flipflops work, so I might try going over mine again using the logic from your schematic.
Cheers
That is not the complete schematic of Timer IC, [I've not shown another comparator whose one input is threshold pin and a discharge logic using transistor]

[If you connect trigger pin to Vcc the negative terminal of that comparator will always be higher than positive terminal so its o/p will always be low and so is the set input of flip-flop, then you cannot set the flip-flop which makes o/p to be low always ]

You can make different type of connections to get phase on and off for around 1 second one way is short trigger and threshold and connect it to capacitor and connect other end of cap. to discharge pin. . .and adjust the resistor value (resistor through which cap. charges and discharges) to get 1 sec on and off time. . .

PS. study the complete Internal structure of timer once, Then you can make all kinds of stuff using timer very easily
 
  • #7
Thanks so much for all your info mate, just found a page now explaining even more about the timer, and showing me the short between the trigger and threshold. From what I can gather I wanted the timer set as an astable and not monostable which I guess I should of guessed from the title of the circuit haha. But it did push me into looking more into the timer and how its built inside and the logic involved. I'm hoping to be able to remake the circuit with the info you've given me hopefully tomorrow. Just another question, in the monostable circuit I was under the impression that the

time=ln(3)R*C

But in the Astable circuit there is two resistors, plus the capacitor, so is the time variable still the same (albeit with R1+R2), or is it only dependent on one resistor??
Here is the site I'm going off of http://www.555-timer-circuits.com/flashing-led.html
Cheers heaps!
 

1. How does a 555 timer circuit work?

A 555 timer is a type of integrated circuit that is commonly used in electronic circuits. It consists of three main components: a voltage divider, a comparator, and a flip-flop. The voltage divider sets the threshold and trigger levels, the comparator compares the input voltage to these levels, and the flip-flop changes state based on the comparator's output. This results in an oscillating output signal, which can be used to control the blinking of an LED.

2. What components are needed to make a blinking LED 555 timer circuit?

To make a blinking LED 555 timer circuit, you will need a 555 timer IC, resistors, capacitors, an LED, a power source, and a breadboard or circuit board to connect all the components together. You may also need a potentiometer to adjust the blinking speed and a transistor to control a high-power LED.

3. How do I calculate the blinking frequency of the LED with a 555 timer?

The blinking frequency of an LED in a 555 timer circuit can be calculated using the formula f = 1.44 / ((R1 + 2R2) * C). R1 and R2 are the resistors in the voltage divider, and C is the capacitor. By adjusting the values of these components, you can change the blinking frequency of the LED.

4. Can I use a 555 timer to control multiple LEDs?

Yes, a 555 timer can be used to control multiple LEDs by connecting them in parallel with the output of the timer. However, this may require additional components such as transistors or buffers to ensure that the LEDs receive enough current to illuminate.

5. What are some common applications of a blinking LED 555 timer circuit?

A blinking LED 555 timer circuit can be used in a variety of applications, such as a simple LED flasher, a traffic light, a timer or countdown display, or as a visual indicator for alarms or alerts. It can also be used in educational projects to demonstrate the principles of electronic circuits and timers.

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