# Ne555p problems. Inexperienced. Help..

#### Bbrandonparran

Joined Sep 8, 2020
24
Okay, so recently got into breadboards and learning about electrical engineering and computers. And by recently I mean 3 days ago.
I have an ne555p chip. I am trying to make an astable clock signa for my projects.
lI have no way of showing a diagram.

R1-2k R2-100k c1 10uf c2 10uf(across + -pins) c3 -0.3uf But I basically followed every YouTube video I can find and it is set up EXACTLY like ben eaters tutorials except I have a 10mf electrolytic instead of a 1mf electrolytic capacitor

I've also tried every combination of R2 and r1 with every possible resistor from 220ohm to 1d ohms and the timing really does not change just flickers very fast??

. So I set it up like that and the light flickers but not at a stable rate. If I put the 2nd 10mf capacitor across the positive and ground pins and it suddenly started pulsing at at bout 2 times a second which seems more accurate. I can also take away that extra capacitor and it stays in a stable pulse. But when I plug anything else into the board interferes with the output signal. E.g. I have a monostable 555 hooked right next to it and when I press my button for the mono stable 555 the astable starts blinking faster. And if I plug in a 74hc393 4bit counter (or any other chip I have ) the astable pulse turns into a flicker but does not count on the clock. Please I'm very new to this and I've been reading and reading all weekend now I've gotten no where if anyone can point me in the right direction or just give me an idea of what's going on. I'll try to post a pic of my set up.

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#### SamR

Joined Mar 19, 2019
3,198
Welcome to AAC! Start with just the NE555, capacitor, resistors and LED. Read the PDF! The 555 timer is the most popular IC of all time and comes in several models. The NE555P is a good start. Look at the timing calculation formula on the PDF. Maybe use a potentiometer to see what the varying resistance does to the timing. Swap out the cap and see how that changes the timing. Become very familiar with the 555 and know what each pin does. Once you have thoroughly become familiar with it, then connect the other components, counters, amplifiers, etc. Learn the components individually before connecting them to make more complex ciruits. Also be aware that fast timers make LEDs blink so fast they can appear to be constantly on. If you have a scope, connect it to the output of the timer and see what it is doing. Good luck!

#### dl324

Joined Mar 30, 2015
12,684
lI have no way of showing a diagram.
Draw it on paper and take a picture. R1 and R2 are meaningless withouta schematic.
ept I have a 10mf electrolytic instead of a 1mf electrolytic capacitor
Do you really mean 10mF? Or 10uF?

For $20, you can get a DSO 138 scope that will let you get a better idea of what's going on. Thread Starter #### Bbrandonparran Joined Sep 8, 2020 24 Welcome to AAC! Start with just the NE555, capacitor, resistors and LED. Read the PDF! The 555 timer is the most popular IC of all time and comes in several models. The NE555P is a good start. Look at the timing calculation formula on the PDF. Maybe use a potentiometer to see what the varying resistance does to the timing. Swap out the cap and see how that changes the timing. Become very familiar with the 555 and know what each pin does. Once you have thoroughly become familiar with it, then connect the other components, counters, amplifiers, etc. Learn the components individually before connecting them to make more complex ciruits. Also be aware that fast timers make LEDs blink so fast they can appear to be constantly on. If you have a scope, connect it to the output of the timer and see what it is doing. Good luck! yes I've spent all of three days messing with it and I feel I had the basics figured out but I'm having trouble with the astable mode. And here's something interesting I did try to hook up potentiometer and the result I got was 70% of the dial gives me a flicker then the last little bit changes to a slightly slower pulse. But nothing in between just two speeds. #### Chris65536 Joined Nov 11, 2019 266 If I put the 2nd 10mf capacitor across the positive and ground pins and it suddenly started pulsing at at bout 2 times a second which seems more accurate. Hmmm. What is your power source? #### MrChips Joined Oct 2, 2009 23,088 NE555 timer circuits cause nasty gremlins to mysteriously interfere with other parts of a circuit. If you can get a hold of CMOS versions such as TLC555 or LMC555 your problems should go away. In the meantime, try putting 10μF across Vcc and GND at the 555-timer chip. #### dl324 Joined Mar 30, 2015 12,684 I've spent all of three days messing with it and I feel I had the basics figured out but I'm having trouble with the astable mode. Take 10 minutes and draw a schematic for us. Using a 555 as an astable is one of its two most basic functions; the other being a one shot. #### dl324 Joined Mar 30, 2015 12,684 @Bbrandonparran It looks like you have two leads in the same hole. You shouldn't do that. Thread Starter #### Bbrandonparran Joined Sep 8, 2020 24 Draw it on paper and take a picture. R1 and R2 are meaningless withouta schematic. Do you really mean 10mF? Or 10uF? For$20, you can get a DSO 138 scope that will let you get a better idea of what's going on.
1st yes I meant uf for microfarad.
2 I've just ordered dso138 kit and multi meter. I feel like I'm working blind without them. And here is my best and first attempt at a curcuit diagram. Hope this is correct. But it matches my set up if you can follow it

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#### Bbrandonparran

Joined Sep 8, 2020
24

#### Bbrandonparran

Joined Sep 8, 2020
24
Hmmm. What is your power source?
It is the breadboard power supply that came with my breadboard kit. I'm using the 5v output but I have no way of verify the actual output tonky board.

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#### Chris65536

Joined Nov 11, 2019
266
It is the breadboard power supply that came with my breadboard kit.
Hey, I see a schematic behind there! Looking over your breadboard picture, I can't find anything obviously wrong. I'm guessing it's something flaky in the wiring or power supply. Or even a bad 555 chip? I have fried my share of them. And yours don't even have any markings on them. Where did you get the chips?

#### Bbrandonparran

Joined Sep 8, 2020
24
NE555 timer circuits cause nasty gremlins to mysteriously interfere with other parts of a circuit.
If you can get a hold of CMOS versions such as TLC555 or LMC555 your problems should go away.

In the meantime, try putting 10μF across Vcc and GND at the 555-timer chip.
yes I have this on my setup currently and it's what I need to make the timer pulse at a realistic rate (relative to my resistors) and once I initially attach it i can remove it and the pulse stays the same.

#### Bbrandonparran

Joined Sep 8, 2020
24
Hey, I see a schematic behind there! Looking over your breadboard picture, I can't find anything obviously wrong. I'm guessing it's something flaky in the wiring or power supply. Or even a bad 555 chip? I have fried my share of them. And yours don't even have any markings on them. Where did you get the chips?
I have 13 ne555p chips from two different sellers off amazon. The markings are there but the more I touch them the less you see of it. I've tried wiring a 5.v phone charger to my board with no avail.

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#### Chris65536

Joined Nov 11, 2019
266
and once I initially attach it i can remove it and the pulse stays the same.
It's not a bad idea to leave the capacitor across the power rails. I usually put 100uF on every breadboard.

#### dl324

Joined Mar 30, 2015
12,684
I've just ordered dso138 kit and multi meter.
When I started doing electronics for a hobby, I only had a power supply, analog meter, and a logic probe. I managed to go for decades without a scope, but they're so inexpensive it doesn't make sense to go without.
here is my best and first attempt at a curcuit diagram.
You've obviously seen schematics drawn that way. Don't use that style and stay away from circuits from anyone who uses it because they probably don't know what they're doing. It conveys more about routing congestion than circuit functionality.

Well drawn schematics will have logic blocks with inputs primarily on the left and outputs primarily on the right. Flow will be primarily from left to right and top to bottom.

Your schematic drawn more conventionally:

This Nat Semi graph gives an astable with a frequency of around 100Hz. The LED will look like it's always on.

#### Chris65536

Joined Nov 11, 2019
266
I have 13 ne555p chips from two different sellers off amazon.
I have no experience buying electronics from Amazon. Who are all these people who have chips to sell? Seems kinda shady to me. Personally, I love Mouser. I just need to scrape enough of an order together to justify the \$8 shipping.

#### dl324

Joined Mar 30, 2015
12,684
I have 13 ne555p chips from two different sellers off amazon. The markings are there but the more I touch them the less you see of it.
Most likely counterfeits. Markings should require a solvent stronger than isopropyl alcohol to remove them.

These days, I wouldn't buy any semiconductors from Amazon or eBay.

Since you're a newbie you should only buy from reputable sources. Otherwise, you can't be sure that the components are good.

#### Bbrandonparran

Joined Sep 8, 2020
24
When I started doing electronics for a hobby, I only had a power supply, analog meter, and a logic probe. I managed to go for decades without a scope, but they're so inexpensive it doesn't make sense to go without.
You've obviously seen schematics drawn that way. Don't use that style and stay away from circuits from anyone who uses it because they probably don't know what they're doing. It conveys more about routing congestion than circuit functionality.

Well drawn schematics will have logic blocks with inputs primarily on the left and outputs primarily on the right. Flow will be primarily from left to right and top to bottom.

Your schematic drawn more conventionally:
View attachment 216754

This Nat Semi graph gives an astable with a frequency of around 100Hz. The LED will look like it's always on.
View attachment 216755
Thankyou for that info I need to practice diagrams because those honestly start to confuse me. Thanks for drawing that up for me. The only difference is R1 is 2kohm and R2 is 100kohm.

#### Bbrandonparran

Joined Sep 8, 2020
24
Most likely counterfeits. Markings should require a solvent stronger than isopropyl alcohol to remove them.

These days, I wouldn't buy any semiconductors from Amazon or eBay.

Since you're a newbie you should only buy from reputable sources. Otherwise, you can't be sure that the components are good.
This is my worry that I spent 4 days now going crazy and its faulty hardware. However besides acehardware I have no idea where to source electronic components. Any suggestions?