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Need "Timer" help right away. Automotive 12VDC Answered

I need a 12 vdc timer that will pass thru 12v once activated, BUT only for about 1 to 1.5 seconds. Then it has to stop passing the 12v even though it is still powered (12v is the still being supplied). Once the supply voltage is removed, it needs to reset so that it can pass thru again the next time supply voltage is introduced. I can solder & read. That is about my limit of electrical circuits. Would an IC 555 timer be able to do this somehow? Thanks STEVE.

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0
verence
verence

5 years ago

Yep. Look for NE555 monoflop. Depending on the load you want to switch you may need a transistor and/or a relay as driver stage.

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st600r
st600r

Reply 5 years ago

thank you Verence. I study the monoflop. I do not know what you mean by "may need a transistor and/or a relay as driver stage:\. Could you explain. Thanks

0
KISELIN
KISELIN

Reply 5 years ago

The 555 would be the perfect solution for You. There's a myriad of solutions for You.

but
there's just one "small.. small.. " glitch with them 555, powering up
they may or may not go to ON position, but using the reset pin (4) you
can eliminate this. I can provide you with a such a thing ,NO ADD is
this, take contact www.teksel.net and I'll give you a total solution, NO
CHARGE, NO ADD HERE, just another enthuisast in electronics.

0
KISELIN
KISELIN

Reply 5 years ago

It is that:you can put a load of max. +200mA or -300mA, (but take care of the cooling). Them transistor providing higher currents, in them schematics are by-passed/ powered by....

0
verence
verence

Reply 5 years ago

The output of the NE555 can only drive a limited current. It is enough for a LED but not for a light bulb or a fan. For this consumers you have to add a transistor (medium currents) or a relay (high currents). In case of the relay even this may need more current than the NE555 can supply and you need both: a transistor to drive the relay.

See this page for some ideas: http://www.bowdenshobbycircuits.info/page9.htm (not affiliated, not checked, was the first thing that came up in a search) Chapter Relay Toggle Circuit Using a 555 Timer shows how to drive a relays with the help of a transistor. Chapter 555 timer Mono stable (one shot) circuit
has the mono flop. Replace the push button with a electrolytic capacitor (try 10..1000µf). When switched on, the cap is discharged and will charge, therefore act as a closed switch. Once it's charged, it will act as an open switch (no current flows). Put a resistor (10k) parallel to the cap to allow it to discharge when the power if off. Those values are just from the back of my head. Use them as a starting point and experiment.



0
KISELIN
KISELIN

5 years ago

The 555 would be the perfect solution for You. There's a myriad of solutions for You.

but there's just one "small.. small.. " glitch with them 555, powering up they may or may not go to ON position, but using the reset pin (4) you can eliminate this. I can provide you with a such a thing ,NO ADD is this, take contact www.teksel.net and I'll give you a total solution, NO CHARGE, NO ADD HERE, just another enthuisast in electronics.