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Old 26th January 2006, 06:33 PM   (permalink)
Default quartz crystal speakers

hi

does anyone know the range of freq of these kind of quartz crystal speakers?

does anyone know if they work at 100KHz or more?

thanks
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Old 26th January 2006, 06:37 PM   (permalink)
Default Re: quartz crystal speakers

Quote:
Originally Posted by epilot
hi

does anyone know the range of freq of these kind of quartz crystal speakers?

does anyone know if they work at 100KHz or more?
It looks to be a standard crystal with the can removed?. It will be highly resonant at one specific frequency, the one it's tuned to, usually in the Mhz region (although lower frequency crystals are available).

I don't see as it's any use as a speaker?.
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Old 26th January 2006, 06:59 PM   (permalink)
Default Re: quartz crystal speakers

Quote:
Originally Posted by Nigel Goodwin
Quote:
Originally Posted by epilot
hi

does anyone know the range of freq of these kind of quartz crystal speakers?

does anyone know if they work at 100KHz or more?
It looks to be a standard crystal with the can removed?. It will be highly resonant at one specific frequency, the one it's tuned to, usually in the Mhz region (although lower frequency crystals are available).

I don't see as it's any use as a speaker?.
yest it is anormal crystal used in these kind of door alarms, i dont know what you call them so i could not find a good pic to put here.

MHZ?
how?, they use in a lot of devices that work at audio ranges?

what kind of speaker i must use for 100KHz?
is the only way using from ultrasonic sensors?
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Old 26th January 2006, 08:31 PM   (permalink)
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I assume this is the type of device you mean, commonly termed a piezo sounder;

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Old 26th January 2006, 08:54 PM   (permalink)
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Quote:
Originally Posted by Dr.EM
I assume this is the type of device you mean, commonly termed a piezo sounder;

yes that is just what i wanted to put here,
thanks for it
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Old 26th January 2006, 10:45 PM   (permalink)
Default

it sems these kind of buzzers can work at very large freq as an ultrasonic sensor alhouh i am not sure?

i want to make a test to see if theu work or not but i have no any equipment to see if it works or not??

i have afew ultrasonic sensors but i have some of problem with them
so i'll try and ask my questions about them tomorrow
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Old 26th January 2006, 11:23 PM   (permalink)
Default

Your transducer is not quartz, it is a cheap piezo. It doesn't have gold, most likely it is brass.
It is probably used in the security device as a vibration sensor/microphone, not ultrasonic. It resonates strongly around 4kHz with very little output above or below. As a microphone it will pickup a glass breaking sound.

Expensive ultrasonic transducers resonate around 40kHz with little output above and below.
I don't know of any transducer that can perform as high as 100kHz.

Why do you need such a high frequency?
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Old 27th January 2006, 12:53 AM   (permalink)
Default

Quote:
Originally Posted by audioguru
Your transducer is not quartz, it is a cheap piezo. It doesn't have gold, most likely it is brass.
It is probably used in the security device as a vibration sensor/microphone, not ultrasonic. It resonates strongly around 4kHz with very little output above or below. As a microphone it will pickup a glass breaking sound.

Expensive ultrasonic transducers resonate around 40kHz with little output above and below.
I don't know of any transducer that can perform as high as 100kHz.

Why do you need such a high frequency?
then do you think my ultrasonic sensors will perfprm at 40KHz?

then if some one wants a 30 or 50KHZ freq what he has to do because such as you said the resonate freq of ultrasonic sensors seems to be near 40KHZ?


i thought about a rangemter and acording to our discussion about ultrasonic and narrow waves i thought perhaps a higher freq buzzer can be good to get more distance, the eson of using buzzers instead of an ultrasonic sensor is because i am not so familiar with them and i read before that they work a freq near 40KHz(please can you explian a bit about them?)

what is difference between a low cost buzzer and a crystal buzzer?
what is the story of "gold"?

hehe sorry for alot of questions, i hope i could get a full answer for my questions :wink:
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Old 27th January 2006, 01:58 AM   (permalink)
Default

Quote:
Originally Posted by epilot
then do you think my ultrasonic sensors will perfprm at 40KHz?
Your sensors aren't ultrasonic.

Quote:
then if some one wants a 30 or 50KHZ freq what he has to do because such as you said the resonate freq of ultrasonic sensors seems to be near 40KHZ?
Digikey sells ultrasonic transducers at 3 frequencies. They are very expensive.

Quote:
i thought about a rangemter and acording to our discussion about ultrasonic and narrow waves i thought perhaps a higher freq buzzer can be good to get more distance, the eson of using buzzers instead of an ultrasonic sensor is because i am not so familiar with them and i read before that they work a freq near 40KHz(please can you explian a bit about them?)
I think they are too small and with low power so the range will be very short.

Quote:
what is difference between a low cost buzzer and a crystal buzzer?
I have never heard of a crystal buzzer. Maybe you mean "ceramic resonator".

Quote:
what is the story of "gold"?
If they use a very thin plating then it won't cost much. I think it is too heavy for a transducer and isn't needed anyway. Cheap brass is fine.
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Old 27th January 2006, 02:27 AM   (permalink)
Default

Quote:
Originally Posted by audioguru
Quote:
Originally Posted by epilot
then do you think my ultrasonic sensors will perfprm at 40KHz?
Your sensors aren't ultrasonic.
no, my meam was my ultrasonic sensoors(referred to my earlier post)not my piezo..


Quote:
then if some one wants a 30 or 50KHZ freq what he has to do because such as you said the resonate freq of ultrasonic sensors seems to be near 40KHZ?
Digikey sells ultrasonic transducers at 3 frequencies. They are very expensive.
then does anyone know any alternative?

Quote:
i thought about a rangemter and acording to our discussion about ultrasonic and narrow waves i thought perhaps a higher freq buzzer can be good to get more distance, the eson of using buzzers instead of an ultrasonic sensor is because i am not so familiar with them and i read before that they work a freq near 40KHz(please can you explian a bit about them?)
I think they are too small and with low power so the range will be very short.
i have 2 big buzzers but it seems you mean they can not peform at 100KHZ nor even at 40 or 50KHZ, if i could use from them... :cry:
Quote:
what is difference between a low cost buzzer and a crystal buzzer?
I have never heard of a crystal buzzer. Maybe you mean "ceramic resonator".

crystal buzzers are what we call that coin buzzers(the above pics)here in my country, i am not sure what is the real name for that buzzers in english(perhaps such as "Dr.EM"said you call them piezo sounder!

Quote:
what is the story of "gold"?
If they use a very thin plating then it won't cost much. I think it is too heavy for a transducer and isn't needed anyway. Cheap brass is fine.


i wait for other helps for an alternative speaker for high freq...

P.s why i can not find any article or tutorial for that coin piezo sounders?
perhaps they have another name that i dont know?
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Old 27th January 2006, 03:08 AM   (permalink)
Default

Google might have a few sentences about a piezo beeper:
"It flexes when AC voltage is applied. It resonates around 4kHz. Commonly used in smoke alarms. It can also be used as a 4kHz microphone."

The piezo beeper transducers I have are much louder with a resonant cavity behind them. A tall bottle cap is good. Sweep the frequency for the loudest peak.
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Old 27th January 2006, 11:54 AM   (permalink)
Default

Quote:
Originally Posted by audioguru
Google might have a few sentences about a piezo beeper:
"It flexes when AC voltage is applied. It resonates around 4kHz. Commonly used in smoke alarms. It can also be used as a 4kHz microphone."

The piezo beeper transducers I have are much louder with a resonant cavity behind them. A tall bottle cap is good. Sweep the frequency for the loudest peak.
only 4KHZ?

i know this coin buzzers abit but i never have worked with ultrasonic sensors so i need help about them too?

i'll try to see if i can find something about them in the net
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Old 27th January 2006, 01:12 PM   (permalink)
Default

Quote:
Originally Posted by epilot
i know this coin buzzers abit but i never have worked with ultrasonic sensors so i need help about them too?

i'll try to see if i can find something about them in the net
Those types of ultrasonic transducers are normally resonant around 40KHz, transmitter and receiver are completely different devices (and are usually labelled T and R) - transmitters are series resonant, and receivers parallel resonant.
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Old 27th January 2006, 02:18 PM   (permalink)
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That's a nice expensive-looking ultrasonic sensor. Post its spec's so we can see if it is a mic or speaker, see how wide or narrow is its beam and how low is its max output power. Then maybe we can figure how much range a pair will make.
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Old 27th January 2006, 06:43 PM   (permalink)
Default

Quote:
Originally Posted by audioguru
That's a nice expensive-looking ultrasonic sensor. Post its spec's so we can see if it is a mic or speaker, see how wide or narrow is its beam and how low is its max output power. Then maybe we can figure how much range a pair will make.
http://www.mstracey.btinternet.co.uk...orysensors.htm

http://www.elexp.com/kit_0a5r.htm

why you call them EXPENSIVE?
i get a couple of those sensors for 1$ !
it seems you call those buzzers and ultrasonic sensors a" expensive transducer" , then i think you are talking about a expensive device not about an element
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