Hi guys,

I was tearing apart a broken microwave and I found this component. It was located at the rear in front of some holes.

Does anyone know what is it??

 

It is called a piezo transducer.
It is used to emit "beep" sounds.

 

It is called a piezo transducer.
It is used to emit "beep" sounds.

 

It is called a piezo transducer.
It is used to emit "beep" sounds.

Yeah thats what I tought at first but it seems like there are two of them?

 

Yeah thats what I tought at first but it seems like there are two of them?

Yep, that's another one.

 

Yep, that's another one.

Oh okay! thank you guys!

 

The piezo transducers are interesting devices and they work the other way, as microphones, also. Bond it to a door and it will hear a knocking, giving you a small voltage. Bond it to window glass and hear all the sound on both sides. Of course you do need an amplifier.

 

The piezo transducers are interesting devices and they work the other way, as microphones, also. Bond it to a door and it will hear a knocking, giving you a small voltage. Bond it to window glass and hear all the sound on both sides. Of course you do need an amplifier.

Interesting!! Do you know why would they use 2 in a microwave? Do they have a different purpose or simply doubling the output?

 

Interesting!! Do you know why would they use 2 in a microwave? Do they have a different purpose or simply doubling the output?

Doesn't your microwave beep when it is done cooking?

 

Doesn't your microwave beep when it is done cooking?

Yes it sure does! But my question was how come there is two of them?

 

Yes it sure does! But my question was how come there is two of them?

Check for a circuit diagram on the inside cover, it may label them.
Max.

 

It may just be that it was easier (meaning cheaper in consumer electronics) to use two than one. If it beeps when you press keys, you would typically want that beep to be fairly quiet, whereas the come-and-get-it announcement you usually want to be fairly loud. Usually the unmounted type aren't as loud as the mounted type.

 

Interesting!! Do you know why would they use 2 in a microwave? Do they have a different purpose or simply doubling the output?

My first guess is that the two give different tone frequencies.. If they did not have some enclosure or mounting, then it may have been just to produce an adequate sound level. But most likely one was for the softer sounds with each key press while the other was to announce the end of the heating time.

 

Interesting thing about Piezo's - they have a preferred frequency much like a crystal oscillator. Piezo's have been used successfully in speakers (tweeters), so they can cover a wider range, but at a certain frequency they will oscillate at their natural resonance and produce the strongest sound they can. Two of them suggests to me that maybe one is for a different tone from the other. Now I gotta run and push buttons on my microwave. No guarantee mine has dual piezo's.

Interesting! Mine has one tone for both the button push and for the alert (end of cook cycle). I hit the wrong button and it gave me an entirely different tone telling me I need to indicate what kind of food I'm putting in. Of course I'm in a hotel, so I can't just open it up and see. But imperial evidence seems to suggest mine MIGHT have two different tone generators.