Timer Delay

Hi,
Is there a really simple module or circuit that I can buy or build that will stall power to a certain device in my circuit for 3 seconds when power is supplied, then will continue as normal?

See diagram below



Thanks

555 Monostable

if you want to use transistors instead of a 555.

the 0-20 seconds is an estimate.

please amend if mistakes are present.
I drew it up in a hurry.



the 2N3904 is not the only usable NPN.
I have almost a thousand of them so I use them where I can.

to answer your other question,
yes, modules are available.

attached are photos of a .1 to 10 second adjustable delay on timer.
They come virtually all times from tenths of a second to days.

the one in the picture costs about 20 dollars US.

it will add a negative to a load after a delay.

any more info needed, jusk ask.

We are open here at AAC 24/7....literally.

The item VoodooMojo showes is called a Delay-On-Make timer or relay. After it recieves power, it will delay the amount you pre-set then let the power continue.

There are also Delay-on-Break to hold another line open after the power to a device is cut off.

But here is a link to a whole bunch of 'em.
http://www.airotronics.com/site/timing_delaymake.php

Hi,
Thanks for your replies. The modules look quite large, is there any really small compact (5volt) Delay-On-Make modules ? It only needs to dealy for 2-3 seconds.

Otherwise I will have to make one myself?

Thanks

2inches by 2 inches.. about 3/4 inch tall. Is that too big?

You want something logic level?

Bills 555 idea will do it. The timer starts when power is added.. Then after the pre-set time, the relay closes to complete the circuit.

Yea, unfortunatley it is too big.

I will look into the 555 circuit. Ideally a pre-built 555 circuit would be great as I just needs this to finish a project off and I don't really want to have to mess around with it and buy all the components.

Jeesh... good luck with that. I have no resource to give you on that..

the 2N3904 is not the only usable NPN.
I have almost a thousand of them so I use them where I can.

Click to expand...

Are you using the first one instead of a diode?
I think it's connection is reversed in the second diagram.

Markd77 said:

Are you using the first one instead of a diode?
I think it's connection is reversed in the second diagram.

Click to expand...

The first 3904 is being used as a Zener Diode to increase the turn on voltage of the other two Darlington connected 3904s.

on the V(BR)EBO spec at Electrical Characteristics of the datasheet it shows the breakdown voltage at a minimum of 6 volts. It is about 8 volts.

The following link might be of help:

http://www.electronics-project-design.com/timedelaycircuit.html

I found that I already have spare 555 timer chip, so I am going to have a go at building a circuit with it tonight.

Thanks for your help

The first 3904 is being used as a Zener Diode to increase the turn on voltage of the other two Darlington connected 3904s.

Click to expand...

Thanks, I get what is going on now.
Nice circuit.