Time delay with relay

dl324

Joined Mar 30, 2015
9,344
Welcome to AAC!

It would be appreciated if you didn't reference circuits in those silly animated simulators that take a long time to initialize.

upload_2017-9-27_7-47-3.png

What is the relay coil resistance and voltage?

What are your restrictions regarding circuit complexity?
 

Thread Starter

Dackie

Joined Sep 27, 2017
5
Sorry about the reference circuit, I don't really have any restrictions on complexity or fixed parts was thinking 12v for the relay. If there's a better way feel free to bin that circuit entirely!
 

dl324

Joined Mar 30, 2015
9,344
Sorry about the reference circuit
I shouldn't have been so harsh for your first post. The preference is for content to be hosted on this site so there are no links to be broken in the future.

This circuit will give about 5 seconds:
upload_2017-9-27_8-18-47.png
EDIT: reduced the size of C2. Original schematic was a redraw of a non-functional circuit; I didn't notice the oversized value until reviewing the post.

The on time is

\( \small T = 1.1R_1C_1 = 1.1 * 470k \Omega * 10uF = 5.17S \)

If the coil needs more than 100mA or so, a transistor will be required.

When you draw schematics, they'll be easier to read if you make them flow from left to right and top to bottom and avoid unnecessary wire jogs.
 
Last edited:

Thread Starter

Dackie

Joined Sep 27, 2017
5
Not sure if that works for my project maybe if I actually explained what I'm doing it might help lol
So I play airsoft and my local site are building a "kill house". I was thinking that i could make a "simulated explosive entry" by using electromagnets to hold a door in the frame until the detonator is pressed, when an igniters would set off the fuse on an airsoft flash bang (with a 4-6 second fuse). The delay is needed so the door doesn't fall as soon as the button is pressed but closer to the time the flash bang goes off. Before I realised about the fuse i was thinking just have the magnets on the NC side of a relay and the igniters on the NO.
 

dl324

Joined Mar 30, 2015
9,344
Not sure if that works for my project maybe if I actually explained what I'm doing it might help lol
The circuit I posted will energize the relay for 5 seconds after the momentary switch is pressed and released. What you have the relay control and how you do it is up to you.
 

Thread Starter

Dackie

Joined Sep 27, 2017
5
The circuit I posted will energize the relay for 5 seconds after the momentary switch is pressed and released. What you have the relay control and how you do it is up to you.
What i need is kinda like a car interior light so after you close the door ( or the relay switches in this case) the NC stayed powered for x time after being disconnected from the voltage supply
 

dl324

Joined Mar 30, 2015
9,344
What i need is kinda like a car interior light so after you close the door ( or the relay switches in this case) the NC stayed powered for x time after being disconnected from the voltage supply
The circuit I provided will power the relay for 5 seconds after being triggered.
 
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