NE555 with solenoid

[Demon]

I'd like to activate a solenoid for a brief moment. Does this timer look correct?



- I added a large cap alongside the solenoid; value is just preliminary.
- the opto is to isolate the solenoid, it will be on a separate 5V line.
- the 10K pot is just to start, I'll bump up to 25K if 110ms is not enough time.


The solenoid will eventually be driven by a PIC, this is only for testing purposes (like figuring out exactly how much correct this thing consumes, how short a pulse of 5V it will accept - I have no datasheet).

Never having used a solenoid before, a quick touch of wire makes it pulse several times. I assume it's normal that it cycles non-stop if I leave it connected - I figure it's the coil charging and discharging.

It's one of these tiny 5V solenoids:

https://www.aliexpress.com/item/1005002278950915.html

[louislouis]

I’m using this circuit.
When the button is pressed, the relay switches on for one second and then turns off.
It doesn’t matter whether the button is pressed briefly or held down - the circuit always activates the relay for a fixed pulse duration.

[Demon]

Can you control duration with this design?

[louislouis]

Of course. By changing the resistance R3, or the value of the capacitor C1, or a combination of both.