Simple Timer application

[TimothyLover]

I need a simple timer that whenever is given current, it lets it pass for a second or two and then switches off. Basically all it needs is send an impulse to an electric lock for it to open and then the circuit should close to avoid to damage/heat the lock. Can be 12 Volts DC or 110 Volts AC as could be placed before or after the transformer. Does anyone know where I could buy this or could someone build it for me for a reasonable price? Any help is appreciated.

Regards
Timothy

 

[mbarazeen]

since what you need is just an impulse, hope the attached circuit may work. it may give you a suden on and off in a fraction of second and this delay is decided by mechanical response delay of the relays.

this is how it will work.

when the circuit get 110V relay R1 picks since it has a path via normally closed (NC) contact of relay R2
when R1 pick R2 also get power via normally open contact (NO) of R1, then R2 will latch since it has another path via its own NO contact, same moment R1 will drop and remain the same.

until 110 v is removed R2 will rmain picked.
R1 just got on and then off and remains.

so the second NO contact of R1 will give you a momentary impulse when you connect your 12v circuit via it. it may be in a fraction of second but of cause much enough to trigger your lock

you dont want to go for any expensive electronic time delays for your need

 

[dougy83]

You can just connect a capacitor inline with a relay coil. The relay contacts are then used to switch the 12VDC to the lock solenoid.

See attached schem. The coil resistance affects the timing; e.g. a G5LE-1-DC12 has a 360 ohm coil, and will switch off after ~0.8seconds with the values shown. Lower coil resistance will result in it turning off sooner. A larger capacitor will extend the time.

The resistor across the supply is to discharge the capacitor quickly (~1.5 seconds) after power is removed so that the lock may be operated again soon.

 

[TimothyLover]

Thanks a lot for your replies and the suggested solutions. Unfortunately I have no clue about electronics and on how to do this. Would anyone be able to do build that for me for a small fee (paypal)?

I live in Panama but also have a mail forwarding address in the US.

Thanks

 

[kinarfi]

https://www.alliedelec.com/search/productdetail.aspx?SKU=4190033
https://www.electro-tech-online.com/custompdfs/2009/12/419-0032PDF.pdf
order one of these
kinarfi

 

[TimothyLover]

Thank you kinarfi. This was exactly what I was looking for. Even though the model you recomendend invloves a Switch, but thanks to your hint I came across

Artisan Controls - 438USA-INT - Allied Electronics

which seems to do just what I need.

Regards and many thanks for your help.