Can you see whats wrong with this flashing LED project

[RichyBell]

Hi guys im a total beginner in the world of electronics. What iv done is buy the book "Electronics for Dummies" and one of the practicle parts of it tells you how to build a flashing LED using a 555 IC. I dont have a 330 ome resistor so i thought id design it on "cirtuit wizard" because i know you can test your projects on there.

As you can see from the attached picture im not able to get it to work but i have no idea why. Iv tried by best to follow the scematics but it still doesnt work. The picture is of the current flow during the testing process im sure you guys will understand it.

This is a list of what parts iv used
555 timer
vr1: 1-m potentionmeter
r2:47k resistor
r3:303 resistor
c1: 1-uF capacitor
c2: 0.1-uF capacitor
LED

 

[LTX71CM]

You've connected the ground of your 9V power supply improperly, it needs to connect on the other side of the LED.

Edit: Like This.

 

[RichyBell]

Hi thanks for the reply i made the change and when i hover over the LED it still says no amp's or watt's? im sure everything is connected correctly though

 

[LTX71CM]

It's been a while since I've used a 555 but every looks good. You have a weird loop coming from the Pin 4 connection but I think it's purely visual and connects properly.

VR1 being at 0% is probably affecting your simulation. VR1 should always be between 10 and 10M OHMs.

 

[jimwill48]

Flashing LED Circuit

Funny thing about this Circuit from Electronics for Dummies.. I built the circuit and could not get it to work with LED. But Sub'ed a 4ohm speaker in place of the LED and could hear the pulses..when LED are in place the LED just stays on solid.....

 

[davenn]

Funny thing about this Circuit from Electronics for Dummies.. I built the circuit and could not get it to work with LED. But Sub'ed a 4ohm speaker in place of the LED and could hear the pulses..when LED are in place the LED just stays on solid.....

which infers that the LED is flashing faster than your eye can detect
slow down the timing period of the 555 timer

D

 

[jimwill48]

That's what I thought but by using the pot I could get the audio pulses down to a couple a second but an LED will still stay solid. I got to admit I got tired of trying to make this work at the time, and I haven't looked at this circuit in a while and guess I should just for my own education..try a new 555 and pot, ecte. I'm still very much a new-by at this....

J

which infers that the LED is flashing faster than your eye can detect
slow down the timing period of the 555 timer

D

 

[jimwill48]

Hummmm..went back and re-built this circuit, works great now that I can tell the diff between a 47ohm resistor and a 47K ohm resistor .

J

That's what I thought but by using the pot I could get the audio pulses down to a couple a second but an LED will still stay solid. I got to admit I got tired of trying to make this work at the time, and I haven't looked at this circuit in a while and guess I should just for my own education..try a new 555 and pot, ecte. I'm still very much a new-by at this....

J

 

[davenn]

Hummmm..went back and re-built this circuit, works great now that I can tell the diff between a 47ohm resistor and a 47K ohm resistor .

J

there ya go a bit of educational experimentation well done

Dave

 

[RichyBell]

Thanks guys, iv noticed quite a few errors in this book but hey its giving me a good starting points