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Timed solenoid

sbw

Dec 18, 2013
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Hi I'm very new to circuit building and am trying to create what should be pretty simple.

I have a solenoid and a power supply. I want to have the solenoid trigger every second. I have a 555 chip but I'm not sure what kind of capacitors and resistors I need to make this work.
Any help would be really appreciated.
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
25,510
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Welcome to Electronics Point.

Can you tell us what voltage and current the solenoid requires.

When you say once per second, that's fine, but for how long?
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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OK, from looking at the specs of these (the catalog page to be exact) it appears that they are rated at up to about 4W. That's not a lot, but it's too much for a 555 on its own.

Here is a page describing the 555 circuit and it allows you to select values for a certain on and off time.

22uF, 27k, and 18k give you the approximate timing I think you require (it works out as on for about 0.7s, and off for about 0.3 seconds.

Then you need to make the output drive a heavier load.

Here is a page describing how to drive motors. (The solenoid is a very similar load). In this case the 555 circuit is a little different, do as per the one above.
 

sbw

Dec 18, 2013
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Steve, thanks so much for your help. If Im reading that second link correctly I would need a BUZ11 Mosfet Transistor to handle the additional power???

As far as a power supply is concerned I have a 12v DC power supply putting out up to 3.2A is that useable for this project ?
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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A BUZ11 mosfet would be fine. It's a much heavier duty device than you need. As long as it's reasonably cheap, that's fine.

Be aware that the gate of a mosfet is easily damaged. I would recommend that you place a 1k resistor in parallel with a 18V zener between the gate and the source. This will make it far harder to damage it once it is in the circuit.

edit: As long as the power supply produces clean DC it will be fine. 3.2A is more than you need so the power supply won't be stressed.
 

sbw

Dec 18, 2013
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does the wattage rating of the 18V zener diode matter?
 
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