NE555p circuit help

[billybob]

I have recently got 20 NE555p ics, and from what I found are the same as the commonly known 555 ic. I have tried sooooooo many simple oscillator designs for at least 3 hours it’s not even funny. I just cant figure out what Im doing wrong. Most circuits are very similar with only a slight resistor change. Here is one that I have tried multiple times on my breadboard. although it’s not the variable design I assume I can switch a resistor for a potentiometer. If anyone can provide some input on the design or an alternate schematic you will save me a lot of stress.

 

[sarahMCML]

Try 5 Volts or more for your power supply as a standard 555 needs a minimum of 4.5 Volts. To run at a lower voltage you need a CMOS version of the chip.

 

[eTech]

The LED is wired such that it will reflect the off time as well.

 

[crutschow]

Apparently someone failed to look at the data sheet.

 

[Visitor]

Apparently someone failed to look at the data sheet.

Billybob is a 16 year old (or so) kid just getting started in electronics. I'm certain he would appreciate your encouragement and guidance more than snide remarks.

Or some helpful advice, like searching for a part on octopart.com to quickly locate a datasheet, and to see distributors who have stock of a particular component. It's a handy resource.

 

[Musicmanager]

I'm certain he would appreciate your encouragement and guidance more than snide remarks.

Huh! Coming from the prolific Master of snide remarks, that's absolutely priceless !

ROFL !

MM

 

[AnalogKid]

There is a reasons why the circuit will not work. On the datasheet, in the table of Electrical Characteristics, note the first item. Compare this to your schematic.

Note that this reason is not related to the distributor.

ak

 

[atferrari]

Most circuits are very similar

Please show just two and then we discuss similarity.

 

[DerStrom8]

In general you'll want the lower resistor (between pins 6 and 7) to be the higher value. As designed, your duty cycle is around 91.7%, so the output off-time will be very short. Since you've got your LED connected to turn on during the output off-time, there will only be a very short flicker (152ms).

Do read the datasheet though, there are other issues that should be taken into account before the above even matters.

 

[Visitor]

I posted a couple of good references on the 555 here. These references should provide reliable circuits and detailed explanations about them.

 

[gophert]

The circuit posted will turn on the LED for about 0.2 seconds every 2 seconds and it should be easy to see.
If you are not seeing it, try
- turning your LED around in case you mixed up anode and cathode
- checking voltage across pins 1 and 8 on your 555 chip in case your breadboard is defective or has a gap in the power rail that you are not aware of
- check if your timing capacitor is really 10uF.

DerStrom8 - the 555 will have a high output 90% of the time but the LEd will only be on 10% of the time since the anode is connected to Vcc (LED will be lit when 555 output is low).

 

[DerStrom8]

The 555 will have a high output 90% of the time but the LEd will only be on 10% of the time since the anode is connected to Vcc (LED will be lit when 555 output is low).

That's why I said this:

Since you've got your LED connected to turn on during the output off-time, there will only be a very short flicker (152ms).

 

[crutschow]

Billybob is a 16 year old (or so) kid just getting started in electronics.

Well, I don't look up the age of every poster.
Apparently you do.
And his age is no excuse for not looking at the data sheet for a device (which is readily found with a Google search) that he is trying to use, especially when it doesn't work as he expected.

 

[Visitor]

No, I just have read some of his posts where he has explained he's just getting started.

But a condescending reply is easier to post than a helpful one.

 

[DerStrom8]

Well, I don't look up the age of every poster.
Apparently you do.
And his age is no excuse for not looking at the data sheet for a device (which is readily found with a Google search) that he is trying to use, especially when it doesn't work as he expected.

It's not so much a matter of looking at the age, but a matter of being kind towards others, especially considering they may be new to electronics and perhaps don't have much experience reading datasheets yet. It takes some practice to read and truly understand a datasheet.

 

[Mickster]

In one of his posts a short while ago, he mentioned that he was at school.

 

[simpleGuy]

If he is a newbie to electronics he should definitely not start with a NE555 or any other opamp, thats way too complex to a "newbie".
But if he just wants to make a led "blink blink blink" with a NE555, there are tons of quick diy youtube videos.

 

[DerStrom8]

If he is a newbie to electronics he should definitely not start with a NE555 or any other opamp, thats way too complex to a "newbie".
But if he just wants to make a led "blink blink blink" with a NE555, there are tons of quick diy youtube videos.

Are you kidding? 555 timers are an excellent introduction to ICs for newbies, and are most certainly NOT "too complex"

 

[MacIntoshCZ]

I used this website for 555

NE555 Astable Multivibrator Frequency and Duty Cycle Calculator

 

[MacIntoshCZ]

If he is a newbie to electronics he should definitely not start with a NE555 or any other opamp, thats way too complex to a "newbie".
But if he just wants to make a led "blink blink blink" with a NE555, there are tons of quick diy youtube videos.

He is playing with few volts. If his power supply cant supply hundreds of amps as mine he should not be scared of anything.
Only his mother i guess =D.
BTW

I think i already post this to him