Pest Repellent

[Mubashir]

I have made a pest repellent circuit, which was download from a web site named "FlashWebHost.com" bc547 transistor based. Accept piezo buzzer all things are same as diagram when i checked ultrasonic frequency that is near about 5000 hz. I need above 20000 hz and below 40000 hz. what i have to do. plz help

 

[akg]

reduce R2,R3, C1 ,C2
refer
https://en.wikipedia.org/wiki/Astable_multivibrator

 

[Ayne]

Simply Use 555 Timer AS Astable_multivibrator...

 

[mramos1]

Search google for a "555 multiviburator online web calculator"

Then you can add a pot and tweak it to what you desire.

 

[Hero999]

5000Hz, shouldn't be ultrasonic, unless you're hard of hearing. Don't use a piezo buzzer in this circuit because it won't work, use a piezo transducer.

 

[HiTech]

It likely won't work well since the freq. should either alternate hi & low or be random freqs. tests show that a single freq. does very little to thwart pests.

 

[audioguru]

The frequency is 5kHz so that your cheap transducer can produce it and so that you can hear it. Then you think that it might do something (it doesn't).
With a supply of only 1.5V it will not be very loud.

 

[mramos1]

5Khz is not only going to bother the cats and dogs. It will bother you as well.

I think a 555 circuit and amp is best for you (like I said before)..

And 1.5 volts. Are you going to duct tape it on their head? Only way they will here it and it bother them.