I'm trying to build a circuit of a Doorbell, but it's very hard to find ICs from local stores.

Doorbell Circuit

I didn't find UM 66. So, someone told me to look for:

  • 3481 series
  • HT3820
  • 4822
  • AM993-9A

Neither of them was found, also.

So my question is:

What other ICs could I possibly use in this circuit? Also, is there a specific site or place where I can search for some ICs and directly find equivalents/similars or it requires knowledge and experience?


For old/obsolete ICs like this, you can sometimes find them on eBay.

Here is one listing from China for the UM66, and another one from France.

Note that there are some unscrupulous semiconductor vendors on eBay so be careful, I would always buy from somewhere like Digikey, Mouser, Farnell, etc if you can (I had a quick look but couldn't see anything particularly suitable)

You could quite easily make a similar circuit using a small micro, a 555 timer or two, using discrete transistors, etc. It depends on your level of knowledge and whether you actually want to design a circuit or simply build an existing one. There are many doorbell circuits/kits out there that do have parts you can find - Velleman make lots of kits, here is a doorbell/tone generator kit that may be of interest.

  • \$\begingroup\$ Thanks for the tips! And yes, I found them, but international shipping takes so long to arrive here, ~2months. =/ I also searched in Digikey, but the search is strange. I find only endless results, a lot of models of ICs who don't even remote to UM 66. So maybe it's better to move on to another circuit. hehe My interest is to build one to learn about electronics. Completely begineer here. I will look for another one. Do you have an idea about an IC easy to find? \$\endgroup\$
    – m3dl
    Oct 5 '12 at 20:48
  • \$\begingroup\$ I don't know of any Two Tone ICs specific for this task, sorry (I would use a small micro). Options easily available from any large vendor like Digikey that come to mind are things like a 555 timer IC or a small microcontroller like a PIC10F. DTMF ICs may be worth looking at too. \$\endgroup\$
    – Oli Glaser
    Oct 5 '12 at 21:14

Sometimes in resource shortage its good to change plan. Some IC become obsolete and may not be available in market.So I'll suggest changing your schematic to some other doorbell circuit by searching on google:-

Example 1

enter image description here

Construct a 9V Door Bell Chime

enter image description here


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