Jump to content
Electronics-Lab.com Community

Timed Beeper...need help!


Mukhalled
 Share

Recommended Posts


Can i use surface mounted capacitors instead of the two capacitors in this curcuit?

Yes, surface mounted capacitors are capacitors.

And what's the value of C2 ? is it nano, piko ...?

This site messes up "u" symbols. Look at the original project at RED Circuits to see that it is a 25uF electrolytic capacitor.

can i use a LED instead of the piezo sounder (just to indicate).

The emitter-follower provides only about 2.3V to the piezo sounder when the 3V battery is new and less voltage when the battery is old which is too low for many LEDs.
Any LED with a series current-limiting resistor can be used if a higher supply voltage is used.

Link to comment
Share on other sites

  • 2 weeks later...

Hi,
I've built this project in a wiring board and it works, so I'm studying the whole ciruit now... but i wonder what function the diode D1 together with R2 has  ???
And if i want to increase the frequency of the (piezo sounder and the LED), i can easily decrease the resistance (R3) or the capacitance (C1), right?

Thanks in advance

Link to comment
Share on other sites


I've built this project in a wiring board and it works, so I'm studying the whole ciruit now... but i wonder what function the diode D1 together with R2 has  ???

R2, R3 and C1 are parts of a classic cmos oscillator. When the output of AND gate IC1D goes high then it stops the oscillator because D1 conducts.
And if i want to increase the frequency of the (piezo sounder and the LED), i can easily decrease the resistance (R3) or the capacitance (C1), right?

Yes, the beeps per second and the flashes per second will increase.
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
  • Create New...