Troubleshooting My 555 Circuit: What Happened and How Can I Fix It?

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SUMMARY

The forum discussion centers on troubleshooting issues with a 555 timer circuit, specifically an IC555. The user initially constructed a blinking LED circuit powered by a 5V printer PSU and experimented with various capacitors and resistor configurations. After incorrectly placing a 33kΩ resistor, the circuit ceased to function as intended, leading to an inability to achieve the desired blinking effect. The user concluded that replacing the IC may be necessary, as the circuit's behavior changed with different configurations.

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  • Understanding of 555 timer functionality and configurations
  • Basic knowledge of electronic components, including resistors and capacitors
  • Familiarity with circuit schematics and breadboarding techniques
  • Experience with power supply considerations in low-voltage circuits
NEXT STEPS
  • Research the proper configuration of resistors and capacitors in 555 timer circuits
  • Learn about troubleshooting techniques for common IC issues
  • Explore the differences between using a 555 timer and an operational amplifier like the 741
  • Investigate the effects of capacitor polarity in timing circuits
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Electronics hobbyists, students learning about timer circuits, and anyone troubleshooting 555 timer applications will benefit from this discussion.

LordVader88
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Did I just fry my IC555 ?

Hi, 1st time poster, long time student/hobbiest of math, physics, most sciences. Just getting serious about electronics lately so I made my 1st 555 circuit ever

I made this blinker , it's a short vid with a very simple schematic in it, he draws it as he goes towards the end. I'm using 5V from an old printer PSU, I used 2 series of 2x 4.7kΩ, the circuit only uses "capacitance" in one place.


I had it working fine and I was trying different capacitors and series/parallel caps.

Then I put a 33kΩ between the neg side of the single cap and pin 1 of the 555 (should of had it before the cap to make a little RC series), and it blocked the current almost completely.

So I took it out and now the circuit won't blink anymore. If I place a short where the cap goes (between pin 1 and 2) the LED lights up and says on. But if I use a cap, the LED lights up for the correct amount of time, but never comes back on. Then if I reverse the cap (not ideal I know), the LED will light up for the correct time.

So I can get the LED to light for the right time, but it never comes back on.

The resistors all still measure correctly, so what happened?
 
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Replace the IC. If the new one works where the old one wouldn't, I leave you to draw your own conclusions ... :wink:
 


only 1 I had, I made another 555 circuit and it doesn't work right either

So I'll have to make some 741 circuits, at least I have a few of them
 

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