Relay connection

[ericgibbs]

wow,did u create that 555 calculator with VB?the 555 timer that u designed to help me,is it a monostable or astable configuration?seen astable to me.I would really like to know the formular on how to calculate the period because my lecturer would want to see how i went about calculating it. is it like T=0.7(R1+R2)C2 ? just to clarify is that buzzer at the bottom of the schematic u posted?which output pin of the cd4024 should i connect the driver to?

hi,
It was VB5, look at the caption bar on the Calc Form, it shows the formula for the mode selected,
Its a an astable configuration for your 555.

I would connect your 12v beeper across the relay coil.

 

[Christy]

Hi sir,
What does (2*Rbot) mean in the formula? i'm still having trouble with the buzzer,please forgive me for these questions,i'm still learning.could u possibly make a visual representation of where exactly i should connect the buzzer with its driver circuit? Thanks sir.

 

[Christy]

Hi sir,
What does (2*Rbot) mean in the formula? i'm still having trouble with the buzzer,please forgive me for these questions,i'm still learning.could u possibly make a visual representation of where exactly i should connect the buzzer with its driver circuit? Thanks sir.

 

[ericgibbs]

Hi sir,
What does (2*Rbot) mean in the formula? i'm still having trouble with the buzzer,please forgive me for these questions,i'm still learning.could u possibly make a visual representation of where exactly i should connect the buzzer with its driver circuit? Thanks sir.

hi,
Have you read thru the 555 datasheet.?
Rbot = Rbottom resistor aka Rb, Rtop= Rtopmost resistor aka Ra

You could connect the buzzer directly across the relay coil, in parallel.
When the relay is energised to switch the light ON, the buzzer will sound.

 

[Christy]

Morning Sir,
I understand now.should i get a buzzer that has a driver circuit already and connect it across the relay coils?just to clarify sir,what diagram is at the bottom of your redesigned schematic circuit?

 

[ericgibbs]

Morning Sir,
I understand now.should i get a buzzer that has a driver circuit already and connect it across the relay coils?just to clarify sir,what diagram is at the bottom of your redesigned schematic circuit?

hi,
I would buy a 12V 'beeper', aka 'sounder' that produces a tone/sound when a DC voltage is applied to its terminals, there are some cheap versions available, about 3KHz is typical.

If you recall the 'user' wanted some idea how much Time had elapsed from when the timer was started. A simple binary indication is a easy way to that, so the transistor driver is for LED's, one for each Qn output.... IF you had NOT been using a relay the same type of transistor driver could have been used to drive a 'beeper'.

OK.?

 

[Christy]

Thanks so much Sir,I think I'm all set now.U have helped me a lot,thanks.if i do have any problems,will try to solve them but i fail to,i will ask you for some help....Enjoy your stay in South Africa next year.

 

[Christy]

Hi Eric,
In your circuit based on the antisleep alarm,the capacitors across the battery and the 555 timer,are they electrolytic capacitors or ceramic?

 

[vne147]

Hi Eric,
In your circuit based on the antisleep alarm,the capacitors across the battery and the 555 timer,are they electrolytic capacitors or ceramic?

For future reference, it’s always helpful if you identify the component you're referring to by number (i.e. C1, C2, C3, etc). Anyway, if you're talking about the schematic that Eric provided in post #32, then:

C1 = ceramic
C2 = electrolytic
C3 = ceramic
C4 = electrolytic

Sorry... I don't know anything about this.So, the interested person can reply me.
The replies will be appreciated.

Thanks....

You’re welcome!

 

[Christy]

Thanks vne!Well I'm new to this forum stuff,but will refer to the components the preferred way next time.Thanks vne for all your help with this thread of mine,thank you too Mr Gibbs.

 

[Christy]

Good morning Mr Eric.Its Christy concerning the antisleep alarm u redesigned.I just want to ask you a question. In the original document explaining what the circuit actually does in this website ().
Thanks sir.

 

[ericgibbs]

Good morning Mr Eric.Its Christy concerning the antisleep alarm u redesigned.I just want to ask you a question. In the original document explaining what the circuit actually does in this website ().
Thanks sir.

hi,
Look at C2 in post #32, its a 220uF, if you make it 22uF it speeds everything by a factor of 10, a 2.2uF would a factor of 100.

So if you experiment with reducing C2 value, you should get close to you new time...OK.???

 

[Christy]

Oh I see now,so i can adjust it till i can get 1 minute?

 

[ericgibbs]

Oh I see now,so i can adjust it till i can get 1 minute?

hi,
By using R1 and R2 values as well, you can get precise timings.

 

[Christy]

Thanks a lot sir, I already calculated the new resistor values for the my timing.

 

[ericgibbs]

Thanks a lot sir, I already calculated the new resistor values for the my timing.

Lets know how your demo goes.

 

[Christy]

Will do Mr Eric.

 

[Christy]

Hi Sir,
I have built the circuit and does not seem to work...I just want know what could be the possible problem.It keeps blowing the fuse of my variable power supply.In your circuit,in post #32,must the supply with the capacitors be connected by the relay side or doesn't it matter?and does CD4024 need a supply voltage and ground ?Aswel as CD4093,is the supply only going to U3 and not the vcc pin?

 

[ericgibbs]

Hi Sir,
I have built the circuit and does not seem to work...I just want know what could be the possible problem.It keeps blowing the fuse of my variable power supply.In your circuit,in post #32,must the supply with the capacitors be connected by the relay side or doesn't it matter?and does CD4024 need a supply voltage and ground ?Aswel as CD4093,is the supply only going to U3 and not the vcc pin?

Hi,
I have added the IC power pins to make the drawing easier to follow.

One end of the 12Vdc relay coil must be connected to the +V12 supply, the other end of the relay coil is connected to the collector of the drive transistor.

The capacitors are connected across the +V12 and 0V as in a regular power supply.

Does this answer you question.??

 

[Christy]

Hi Mr Gibbs,
I have found the short the was causing the fuses to blow.I have another problem.the circuit does not reset nor will the beeper stop beeping continiuosly...i have tested it without the ac applied to the relay contacts...the relay is always energized when the i apply supply to the circuit keeping the beeper on.what could be the problem?