• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Buzzer operation using NPN transistor

Status
Not open for further replies.

alok1982

Member
Hi All,


I want to switch ON a LED and a Buzzer by using transistor. Both are connected to a single NPN transistor 2N2222.


Input to the base of transistor is coming through a comparator. Is this is the right way?


Also, can I use Piezo buzzer for my application? There’s no frequency generation in my application.


Please see the attached picture for your reference.


Thanks!
 

Attachments

ericgibbs

Well-Known Member
Most Helpful Member
hi alok,
You could use a acoustic sounder/bleeper instead of a piezo.
The sounder will work directly from 12v
E
 

Attachments

alec_t

Well-Known Member
Most Helpful Member
Your LED current will be about 33mA. Isn't that excessive?
 

ericgibbs

Well-Known Member
Most Helpful Member
hi,
The piezo will need to be driven by a square wave signal in order for it its to generate sound, say approx 3kHz.
Look at the 555 IC device.
E
 

audioguru

Well-Known Member
Most Helpful Member
A piezo beeper (sounder?) has an oscillator inside it. It is powered from 3VDC to 24VDC. Its current is only about 10mA when it has a 12VDC supply so it can be parallel to the LED and its resistor. The diode is needed only for a "magnetic" buzzer, not for a piezo beeper.
 

AnalogKid

Well-Known Member
Most Helpful Member
In case it is not clear from the posts so far, there are two types of piezo beepers. One is a bare piezo element and needs an oscillator circuit. The other has the oscillator circuit built in, and can be connected directly to a DC power source. Unfortunately, both can be packaged in the same round case, so there is no obvious difference to tell them apart. Do you know the manufacturer and part number of the piezo device you are using? Can you post a link to its datasheet?

ak
 
Status
Not open for further replies.

Latest threads

EE World Online Articles

Loading
Top