Design Help Needed

[vandor]

wondering why my explanation post of d tutor design doesn't appear rite now.
i alrdy tried to post two times... with attachment.


Shermaine is in hurry.

 

[shermaine]

Hi guys,

i have put the resistors at the 555 timer and the capacitor, however, there isn't any led light up. Did the test, but seem like red led is on without flashing.

 

[shermaine]

hi there vandor,

appreciate if you could email to me now. Thanks!

 

[vandor]

updated tutor design edition.

 

[ericgibbs]

hi vandor,

Dont post other members thread outdated drawings.

This thread is confusing enough already.

 

[ericgibbs]

hi shermaine,

If you have wired the spare 7410 gate up as shown and you are getting a steady light on the LED, it might be one of the following.
[does the LED go OFF when you connect the test probe to 0 Volts ??]

The 555 is not wired correctly or its faulty.

The timing components R1/R2 C1 may be wrong values, look at the datasheet and make sure the components are for a 1 HZ clock rate.
What component values are you using?

 

[vandor]

hi vandor,

Dont post other members thread outdated drawings.

This thread is confusing enough already.

sorie , tat confusing one is the tutor design and working here well.

 

[shermaine]

Hi eric,

i never test the test probe on 0 volt. Basically, i was using an extra red led to connect to 7410> it does light up the both the 2 red leds. I'm not sure if the capacitor volatge was affecting the 555 timer. What is the ideal volatge to be used? Basically, when i d/c the cap, with resitor on, the red light is on.

 

[shermaine]

Hi,

I'm using Ra = 68k, Rb = 39k and C = 10 uF.The voltage me using is 63V. Does this voltage affect?

 

[ljcox]

Hi,

I'm using Ra = 68k, Rb = 39k and C = 10 uF.The voltage me using is 63V. Does this voltage affect?

The voltage is irrelevant. It just needs to be > 5 Volt, so 63 V is OK.

Is the oscillator working? Did you connect Eric's probe to it as he suggested? If so, did it flash?

 

[ljcox]

Hi eric,

i never test the test probe on 0 volt. Why not?
Basically, i was using an extra red led to connect to 7410> it does light up the both the 2 red leds. I don't understand this sentence.

I'm not sure if the capacitor volatge was affecting the 555 timer. What is the ideal volatge to be used? Basically, when i d/c the cap, with resitor on, the red light is on.
See my previous post re the cap voltage. What red light are you refering to? The one connected to U3/12 or the one connected to Eric's logic probe?

You need to make your posts more understandable. They are too vague.

 

[ljcox]

Did you orient the capacitor correctly?

The negative plate must be connected to Gnd.

It may be damaged if you connected it the wrong way around.

Do you have another one? If so try it.

 

[ljcox]

Hi eric,
Basically, when i d/c the cap, with resitor on, the red light is on.

This sounds to me like the capacitor is shorted. You probably connected it the wrong way around and damaged it.

Replace it with another one and make sure the negative plate is connected to gnd.

 

[shermaine]

Hi guys,

I have change a new capacitor and it still the same. It only managed to light up the red led.

 

[ljcox]

Hi guys,

I have change a new capacitor and it still the same. It only managed to light up the red led.

Which red LED? The one on U3/12 or the one used for Eric's probe circuit?

Have you connected the 555 as shown in the data sheet?

Have you checked the connections? Is pin 1 of the 555 connected to gnd?

Is pin 4 open or connected to +5 Volt?

What voltages do you measure on pins 2, 5, 6 & 7?

What voltage do you measure on pin 3?

Is there someone who can help you? It would be much easier to advise you if I could be with you in person.

I just did a Google search on "555 Timer" There were plenty of hits. Here are a few.

**broken link removed**



**broken link removed** (follow the astable link)

http://www.williamson-labs.com/480_555.htm

**broken link removed**

http://www.kpsec.freeuk.com/555timer.htm

http://en.wikipedia.org/wiki/555_timer_IC

**broken link removed**

 

[shermaine]

hi guys,

thanks a lot for ur help. My bro did the troubleshoot for me and it works fine now. Thanks a lot for u guys effort in providing advises n knowledge! Appreciate that!

 

[ljcox]

You're welcome.

Thanks for letting us know. Some people don't bother.