Help! Cant get this circuit to work any ideas? Thanks

Thread Starter

Evan18

Joined Nov 14, 2016
8
Reasons why it may not be working.

1: Power supply issue ---------------> Check for correct voltage & polarity
2: Incorrect wiring----------------------> Check wiring
3: Faulty components----------------> Check components, does LED work, is pot shorted or open circuit ?
4: Incorrect values used------------> Are resistors correct value ? Is your cap the correct value ?

What do you think your frequency range should be ?
Im new to this and this is not my design. somebody used these measurements for the same function i intend to. i know im using a 10k trim pot instead of a 150k. Could that cause the led speed not to change? What about the order i place the wires to my prototype board? other than that power supply and components are fine.
 

Thread Starter

Evan18

Joined Nov 14, 2016
8
Changing the value of the pot will affect the frequency.

With the values shown (changing the pot for 10K) you will have a range from 22.5hz to about 5.5hz.

The LED may not appear to be flashing to you. As long as the wiring goes to the right place it should work.

This link may be of help in choosing some values to slow the circuit down to prove the circuit at a slower rate.

http://www.ohmslawcalculator.com/555-astable-calculator
It flashes just at a slow rate that i cant adjust using my trim pot. i can tell it flashes once anout every 5 seconds and cant be adjusted with the trim pot
 

Thread Starter

Evan18

Joined Nov 14, 2016
8
Going by the values you have given you are not even close to the frequency you should be getting. Check the link I gave you and put in the values you have given.
I should be getting a higher frequency which will cause the light to blink faster correct? Now when i plug my trim pot in the LED doesnt light up but when i remove the trim pot it does.
 

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Alec_t

Joined Sep 17, 2013
10,424
Now when i plug my trim pot in the LED doesnt light up but when i remove the trim pot it does.
Sounds like a wiring error then. Have you used the correct pinout for the pot? Usually the middle pin of three is the wiper, but you should check.
 

Dodgydave

Joined Jun 22, 2012
8,464
Have you got a voltmeter or dvm, you can check if its working better,, your circuit shows there are (two pin 7) the breadboard looks correct,

to check if the chip is working, temporarily link pins 1,2 together and the led should light continously,

then link pins 2,4 together the led should go out.
 
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