circuit question number one.

You want this when switch closed -



OR this -



Regards, Dana.

If you want the LED/buzzer to do the opposite of what it is currently doing, connect the resistor/LED between the +5V rail and pin 3.

Hi,
It would perhaps be easier to use a CD4049 Quad inverting buffer IC instead of the 555, in conjunction with a DC operated piezo-buzzer such as https://www.rapidonline.com/r-tech-350204-12v-pcb-piezo-sound-generator-3-20vdc-35-0204. The attached schematic shows the required connections. The buzzer has a built-in oscillator and only requires DC voltage to work. It consumes 15mA. The 4xganged inverters shown in the schematic will supply enough current for both the LED & buzzer. The schematic only shows the LED. To also connect the buzzer, connect its +ive terminal to the joined up outputs of the inverters and its -ve terminal to earth.

There are 6 inverters in the CD4049, and you can connect all 6 just as I have shown with 4 of the inverters (ie ganging up all 6 together)

EDIT: 08 Mar 2025. I had inciorrectly labelled the two schematics. I have now swapped over their labels and they are now correctly labelled

Thanks to everyone that responded, much appreciation is due. I will try these solutions and eventually post.

ramuna,
Do you have a part number for CD4049 Quad inverting buffer IC ?

Wes76 said:

part number for CD4049

Click to expand...

That is its manufacturers part number. (There are also other makes with different prefixes, but still the same "CMOS 4049" IC).

You should be able to get them at any place that sells components, including amazon & ebay etc.
eg.

rjenkinsgb , I looked on Digikey, but only saw the "hex" version. I'll try the specific part numbers.

CD4049UBE comes up as 6 channels (hex not quad) Am I missing something about the specific part?

Wes76 said:

CD4049UBE comes up as 6 channels (hex not quad)

Click to expand...

It is a hex buffer; the poster mentioned that later, the first mention incorrectly says Quad. Many 4000 series ICs with two-input gates are quad devices, so just a typo.