Question about a circuit using a 555 timer

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SUMMARY

The discussion revolves around the operation of a 555 timer circuit configured in astable mode, specifically addressing the effects of adjusting a 100k Ohm potentiometer to 0 resistance. When the potentiometer is set to zero, the capacitor discharges rapidly, resulting in a continuous high output that risks damaging the internal transistor of the HA17 555 timer. Additionally, a user reports issues with their timer not pulsing correctly at 6.5 Hz, experiencing overheating and continuous buzzer activation, which may indicate incorrect pin connections or a damaged timer.

PREREQUISITES
  • Understanding of 555 timer configurations, specifically astable mode
  • Basic knowledge of electronic components: resistors, capacitors, and potentiometers
  • Familiarity with circuit simulation tools like Multisim
  • Experience with troubleshooting electronic circuits and components
NEXT STEPS
  • Research the effects of resistance values on capacitor discharge rates in 555 timer circuits
  • Learn about the pin configuration and functionality of the HA17 555 timer
  • Explore troubleshooting techniques for non-pulsing 555 timer circuits
  • Investigate safe operating limits for 555 timer components to prevent overheating
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Electronics enthusiasts, hobbyists building timer circuits, and engineers troubleshooting 555 timer configurations will benefit from this discussion.

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Here's the drawn circuit: http://imgur.com/DGo9M.png

R1 is 10k Ohm resistor
Pot is a 100k Ohm potentiometer
C is 1.0uF Electrolytic Capacitor

My question is, what happens when the potentiometer is turned down to 0 resistance? Would the circuit fry?

thanks
 
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Pin 7 discharges the capacitor after it has fully charged. So, if you made the resistor almost zero, the capacitor would discharge very quickly.

This produces an output that is mostly high but with a very short low time.

If you could make the resistance zero, the output would stay high all the time but there is a risk that the transistor that discharges the capacitor (inside the chip) could get damaged, especially if a large electrolytic capacitor was used.
 
problem with my HA17 555 timer

i recently bought my 555 timer and i simply can't get it to pulse. I flick on the switch and i get my buzzer to work that is connected to the output but i don't hear it turn off and on. I set my configuration as astable 6.5 Hz. i checked all my connections and everything seems right. However during my first run, i connected my timer circuit parallel to 1k that was instead of two 1k connected with source along with 30 ohms the circuit (that gave off 9v 8mA). And during my first 2 runs my timer was heating up really fast. After adding another 1k to the source (as the pic) i was able to get 5V and then it didn't heat up. I even checked my simulation with multisim and despite of that i don't get any pulse (the buzzer jus keeps going and no beep).

I am thinking its either i burned my timer or i got the pinning wrong. Check both my image files to see i am doing anything wrong. Btw 9V with 30 ohms in series depicts my adaptor that gives off 9V with 300 mA

Download file from link below.


http://squadinvenire.uuuq.com/555_timer.rar
 
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