I need a schematic...

I need a schematic for a circuit using a 555 timer. I want a switch to activate the timer, which will provide 3 volts to a buzzer for one second, no matter how quickly the target is hit.

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jeff-o7 years ago
Here you go!  All you have to do is plug in values until you get the result you want.

Monostable oscillator

You'll want to switch the buzzer using a transistor, since they can draw a lot of current.
XOIIO (author)  jeff-o7 years ago
Thanks, but how exactly would I plug it in? I have literally no clue what I would need for the resistor and capacitor.
jeff-o XOIIO7 years ago
Using that calculator, C1=330uF and R1 = 8.2k should get you close.  But be aware, the value of the capacitor can vary by as much as 20%, so your timer may not hit 3 seconds precisely (or in this case, exactly 2.9 seconds).  If it needs to be really close, include a 1k ohm potentiometer in series with R1 to "trim" the timing to a precise time period.

Also be aware that with this circuit, the timing will only start once the button is released.
XOIIO (author)  jeff-o7 years ago


*Runs giddily to the electronics store*

Goodhart jeff-o7 years ago
Um,  3 seconds?   I think he wanted a one second burst.
jeff-o Goodhart7 years ago
Whoops!  I still had "3 volts" in my head.

Make that C1 = 100uF and R1 = 9100 ohms.
Goodhart jeff-o7 years ago
that sounds a little better ;-)