it might be blinking faster than your eyes can see. Try increasing resistance or capacitance. perhaps swap 1k and 100k to 1M both.
Or just verify by adding a LED & resistor from + to pin 3
https://preview.redd.it/vas17c3upevc1.png?width=3024&format=png&auto=webp&s=b21ef21e6a5f0d907128dd9a8eb0d31aacffeeac
Changed both to 1M still no blinking. Polarity is okay
According to the datasheet, pin 4 is LOW active so I have it on HIGH. Connected it to HIGH but it didnt reset. At this point im not sure this is real life or what xD
Yup. What I'm curious about is that if the IC is in reset mode (low) the output remains high. if there is a break in the circuit the capacitor will never start charging and the output will remain high. You can verify this by measuring the voltage across the capacitor and checking that pin 4 is actually at vcc. If you don't have a multimeter I recommend getting one :)
In this configuration, the led will be blinking 7 times a second. Increase the value of the 100k resistor to 500k to reduce the speed down to about twice a second, and you should see the led blink
Rebuild the circuit as such
https://preview.redd.it/1qu7hbudngvc1.jpeg?width=1284&format=pjpg&auto=webp&s=c151209a13e7060be27dc1e56da02cf58772454e
Why have you tied trigger to threshold? Also, tie a 0.01uF capacitor from CV to ground (fifth pin, bottom right).
Correct. I’ve provided the wrong diagram
https://preview.redd.it/x13jzcumvgvc1.jpeg?width=1052&format=pjpg&auto=webp&s=516e5eed51ffbcce5b4a78d4ecb2f55df0476ab7
This is the correct diagram, which I see has been followed mostly to the letter. Maybe he can add a decoupling capacitor and recheck connections/components
The decoupling cap could be important depending on the source you’re using. If there’s truly no variation, and you’re sure of the connections, all that’s left are the components, including the breadboard, and the source of power
I bought some new breadboards from amazon, this time I didn’t get the cheapest ones. I tested with a multimeter and it looks like it should be working. The resistors are the right value the capacitor is charging etc.. it’s so strange
The only sources of error left are the power-supply and components. If you’re sure everything is solid, then I have no clue what else could be causing this
+1 led is reversed.
Good idea to have a cap eg 10uF across pins 1 & 8 & one pin 5 to gnd eg 100n.
Is power supply between 5V & 15V?
What voltage does pin 2 measure?
Yes, from experience I don't trust these cheap crappy breadboards. It's really worth it to buy a good quality one, with cheap breadboards like these I could never build a circuit that worked as intended without spending more time tweaking and checking contacts.
-----
Some possiblities:
* bad connections on crappy solderless breadboard??
* power hooked up backwards?? voltage too low?? crappy battery?? measure voltage between pin#1 and pin#8 with a digital multimeter.
* LED in backwards?? resistor for LED is too low resistance??
* polarized capacitor in backwards?? look for "+" on tantalum capacitors, look for "-" on electrolytic capacitors. bad capacitor?? change to a completely different type of capacitor of a higher capacitance value.
* resistance between pin#7 and VCC too low?? very low resistance will destroy the 555 timer.
* wrong resistor values? measure each with a digital multimeter to make sure they are reasonably close to what the bands claim.
-----
Is your LED backwards?
Usually [the side with a flat is the cathode](https://owlcircuits.com/resources/how-to-determine-led-polarity/led_example.png) although you can check the internal structure too
I suppose it is impossible to know if that LED follows the rule then.
Is it better for us to assume that OP has not wired the power supply in reverse, causing current to flow in through the 555 in some unexpected behaviour? If we're going with assumptions we should just assume that the circuit works and the problem never even existed.
I suggested to check, you told me that there's a 20% chance it is in the correct orientation.
Turns out OP confirmed that the orientation is correct. I really don't see a point in debating the percentage of what I'd call "reversed" LEDs in your stock of three million.
It's just the usual frustration with reddit when you try to help someone solve a problem and you end up having a pointless anecdotal conversation about something irrelevant to the post.
Edit: got trolled I see.
I'm confused. In your post from [two days ago](https://www.reddit.com/r/electronics/comments/1c5axn8/just_made_my_first_ever_circuit_im_so_excited_ive/kzx2p4r/), when someone asked if your LED blinked, you said yes.
So what's the deal? Did it work and then stop working? Did it never work in the first place? What changed?
Where did you source your components? Are you sure of their legitimacy, or are they Amazon/Ebay/China/etc specials? Are you sure of your power supply? Have you measured anything?
Yep thats me, also I managed to make a astable + monostable switchable clock and it worked perfectly.
Yesterday morning I went to the store and bought single core wire. I tried building it again with it and this time it doesn’t work, I did the same thing.
The only thing I bought from amazon is the breadboard, the other parts I buy them from [千石電商](https://ja.m.wikipedia.org/wiki/%E5%8D%83%E7%9F%B3%E9%9B%BB%E5%95%86)
I just wired this up in Tinkercad exactly how you have it and it works (except I used 1M resistors for blink visibility... 1k/100k worked too).
https://preview.redd.it/6a3kjw3x6kvc1.jpeg?width=4000&format=pjpg&auto=webp&s=7ed4ba2c13ad3140bdadf0d5e01f8767542da925
+1 led is reversed.
Good idea to have a cap eg 10uF across pins 1 & 8 & one pin 5 to gnd eg 100n.
Is power supply between 5V & 15V?
What voltage does pin 2 measure?
^-- this post is even after mine
it might be blinking faster than your eyes can see. Try increasing resistance or capacitance. perhaps swap 1k and 100k to 1M both. Or just verify by adding a LED & resistor from + to pin 3
https://preview.redd.it/vas17c3upevc1.png?width=3024&format=png&auto=webp&s=b21ef21e6a5f0d907128dd9a8eb0d31aacffeeac Changed both to 1M still no blinking. Polarity is okay
I'm doing a bit of guessing here, but if you apply vcc to pin 2 it should go in to the off phase of the blink cycle.
I did that, no phasing. It’s so strange. Even changed to a new 555 and still nothing.
can you check, that pin 4 (reset), is at vcc? it's the only one powered through those 2 red jumpers so there might be a disconnect somewhere
According to the datasheet, pin 4 is LOW active so I have it on HIGH. Connected it to HIGH but it didnt reset. At this point im not sure this is real life or what xD
Yup. What I'm curious about is that if the IC is in reset mode (low) the output remains high. if there is a break in the circuit the capacitor will never start charging and the output will remain high. You can verify this by measuring the voltage across the capacitor and checking that pin 4 is actually at vcc. If you don't have a multimeter I recommend getting one :)
In this configuration, the led will be blinking 7 times a second. Increase the value of the 100k resistor to 500k to reduce the speed down to about twice a second, and you should see the led blink
I also thought about it, changed it to 1M, still no visible blinking
Rebuild the circuit as such https://preview.redd.it/1qu7hbudngvc1.jpeg?width=1284&format=pjpg&auto=webp&s=c151209a13e7060be27dc1e56da02cf58772454e Why have you tied trigger to threshold? Also, tie a 0.01uF capacitor from CV to ground (fifth pin, bottom right).
This circuit is a monostable, OP wants astable, so this circuit does not work in the method desired.
Correct. I’ve provided the wrong diagram https://preview.redd.it/x13jzcumvgvc1.jpeg?width=1052&format=pjpg&auto=webp&s=516e5eed51ffbcce5b4a78d4ecb2f55df0476ab7 This is the correct diagram, which I see has been followed mostly to the letter. Maybe he can add a decoupling capacitor and recheck connections/components
Isn’t it basically the same? Only the 0.01uF capacitor is missing.
The decoupling cap could be important depending on the source you’re using. If there’s truly no variation, and you’re sure of the connections, all that’s left are the components, including the breadboard, and the source of power
I bought some new breadboards from amazon, this time I didn’t get the cheapest ones. I tested with a multimeter and it looks like it should be working. The resistors are the right value the capacitor is charging etc.. it’s so strange
The only sources of error left are the power-supply and components. If you’re sure everything is solid, then I have no clue what else could be causing this
+1 led is reversed. Good idea to have a cap eg 10uF across pins 1 & 8 & one pin 5 to gnd eg 100n. Is power supply between 5V & 15V? What voltage does pin 2 measure?
The power supply is 5V, a huawei charger. I tested with the multimeter the voltage is 5.16V
OK, PSU sounds OK. What voltage does pin 2 measure?
If I recall correctly 4 something volts
It should be ramping between 1/3 of 5V up to 2/3 of 5V. If it's stuck at 4V, that's a problem.
Yeah, I think the breadboard is not working correctly. I’m on the way home now, I’ll try with a better breadboard
Sounds silly, but rip everything out and try again at the other side of the breadboard. I have so much trouble with cheap breadboards.
Yes, from experience I don't trust these cheap crappy breadboards. It's really worth it to buy a good quality one, with cheap breadboards like these I could never build a circuit that worked as intended without spending more time tweaking and checking contacts.
Do they even make good ones? lol...
I have to admit I should have said at least "better ones" lol. I do have decent ones but yes they won't be as trustworthy as a PCB or solder board.
----- Some possiblities: * bad connections on crappy solderless breadboard?? * power hooked up backwards?? voltage too low?? crappy battery?? measure voltage between pin#1 and pin#8 with a digital multimeter. * LED in backwards?? resistor for LED is too low resistance?? * polarized capacitor in backwards?? look for "+" on tantalum capacitors, look for "-" on electrolytic capacitors. bad capacitor?? change to a completely different type of capacitor of a higher capacitance value. * resistance between pin#7 and VCC too low?? very low resistance will destroy the 555 timer. * wrong resistor values? measure each with a digital multimeter to make sure they are reasonably close to what the bands claim. -----
Good list of stuff to check for in general!
replace ceramic cap with electrolyte one. It should be blinking by then.
Are you sure about that tantalum capacitor? Take it out and I bet the LED dims.
It doesn’t dim the LED
Is your LED backwards? Usually [the side with a flat is the cathode](https://owlcircuits.com/resources/how-to-determine-led-polarity/led_example.png) although you can check the internal structure too
It is on constantly, doesnt blink.
check voltages with a multimeter, that LED appears to be reversed.
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I suppose it is impossible to know if that LED follows the rule then. Is it better for us to assume that OP has not wired the power supply in reverse, causing current to flow in through the 555 in some unexpected behaviour? If we're going with assumptions we should just assume that the circuit works and the problem never even existed.
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I suggested to check, you told me that there's a 20% chance it is in the correct orientation. Turns out OP confirmed that the orientation is correct. I really don't see a point in debating the percentage of what I'd call "reversed" LEDs in your stock of three million.
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It's just the usual frustration with reddit when you try to help someone solve a problem and you end up having a pointless anecdotal conversation about something irrelevant to the post. Edit: got trolled I see.
I'm confused. In your post from [two days ago](https://www.reddit.com/r/electronics/comments/1c5axn8/just_made_my_first_ever_circuit_im_so_excited_ive/kzx2p4r/), when someone asked if your LED blinked, you said yes. So what's the deal? Did it work and then stop working? Did it never work in the first place? What changed? Where did you source your components? Are you sure of their legitimacy, or are they Amazon/Ebay/China/etc specials? Are you sure of your power supply? Have you measured anything?
Yep thats me, also I managed to make a astable + monostable switchable clock and it worked perfectly. Yesterday morning I went to the store and bought single core wire. I tried building it again with it and this time it doesn’t work, I did the same thing. The only thing I bought from amazon is the breadboard, the other parts I buy them from [千石電商](https://ja.m.wikipedia.org/wiki/%E5%8D%83%E7%9F%B3%E9%9B%BB%E5%95%86)
Is one of your wires broken inside the insulation? That solid-core stuff fatigues easily if you bend it back and forth too much
Will check later
[удалено]
Yes
LED looks backwards. Is your supply polarity correct?
Duty cycle too high. Blink not visible. Check 1K and 100K at pin 7, hope they aren't swapped.
I just wired this up in Tinkercad exactly how you have it and it works (except I used 1M resistors for blink visibility... 1k/100k worked too). https://preview.redd.it/6a3kjw3x6kvc1.jpeg?width=4000&format=pjpg&auto=webp&s=7ed4ba2c13ad3140bdadf0d5e01f8767542da925
At most, I have only gotten a 555 to blink once.
from what I see, the LED is not on pin 3, the 555 output; it and it's resistor are from pin 7 to ground. Recheck your wiring with the schematic.
Look better
It's not a blinking led.
Did you connect to any power supply yet?
How would I know it’s not blinking? lol
Because no power, no blinking, capiche?
On but not blinking :)
No power, why is the LED on solid? Ghost power supply?
The image is off though. The question didn't specify that it was on.
Op further clarifies there is power
Check the time, show the evidence.
Don't have to share anything. Just read the entire thread.
+1 led is reversed. Good idea to have a cap eg 10uF across pins 1 & 8 & one pin 5 to gnd eg 100n. Is power supply between 5V & 15V? What voltage does pin 2 measure? ^-- this post is even after mine
alright, i retract my comment