First thing, I'm a newbie in creating electronic projects. I've just been studying the basics. I need help on this please. Anyone who can help me will be much appreciated. We need to assemble the following circuit:



Sorry, if the image is large, I don't know how to change the size in BBcode.

The circuit is freely available and I think we can build it.

The author made a note about the schematic. But I need to clarify certain points. The quoted phrases are from the author, next each of them is my question.
1. Is this true? Isn't this frequency harmful to humans (even if we can't hear this)?

1. Can I replace CA3130 with UA741? I have researched and they have the same pin configuration, but different technology. Can it affect the output?
2. Can I replace CD4017 with HEF4017B?

1. What values should we use for VR1-6.
2. We are using trimmer resistor for this. Is it correct? Should we use different var resistor?

1. I'm lost. Please explain. =(

1. Can we replace CD4013 with HCF4013? What effects, if any?
2. What tweeter? We have been looking for this part. All we found were piezoelectric tweeters with frequency of 5-20kHz. We didn't get it. After asking someone, he told us to use transducer. We bought it and it looked like a thin penny. Can it produce the frequency we need? And does the 5-20kHz piezoelectric tweeter can do the job of outputting 30-40kHz? <-dumb question

1. How can we do it by trial and error if we can't hear the sound?

1. Can we buy crystal transducer? What is it like? Are there specs when it comes to transducers? Coz we bought a transducer and the seller didn't ask us about frequency output.

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-zeit-

 

1. By the way, we are planning to use generic power supply adapter, from 220 to 12V. The output tells 500mA. Can we use that? Can the ICs receive current as high as 500mA?

2. We would like to put LED for "power indicator". What resistor value should we use? I have read and found out that about 30-40 mA and 2V is suitable for LEDs. How can I reduce the voltage from 12v to 2v along with the current from 500mA to 33mA?

3. We would like to put a flashing LED for "gadget working indicator". How can we build that?

Thanks in advance.

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-zeit-

 

Use Ohm's law to answer questions one and two.

Light Emitting Diodes (LEDs)

Use a flashing LED.
5mm Flashing LEDs > Maplin
flashing LED - Google Search

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I do not answer private messages asking for help because no one else can: benefit from advice I may give or correct me if I'm wrong.

Please ask on the open forum if you have a question and I'll be happy to help, if I know the answer.

 

The circuit was tested with a tiny telephone ceramic earpiece, not a powerful tweeter.

Where are you going to find a tweeter that produces ultrasonic frequencies and can survive high power? The piezo tweeters that were used in old PA speakers barely made it as high as 18kHz. Continuous power destroyed them nearly as quickly as normal tweeters.

A HEF4017 is exactly the same as a CD4017B but costs much more because it is a "replacement".
The lousy old 741 opamp will work fine as the low frequency oscillator opamp.

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Uncle $crooge

 

Hi,

to calculate for the power LED resistor use Ohm's law as already posted.

Subtract the LED forward voltage from the supply voltage to obtain the correct current limiting resistor.

The CD4017 is manufactured by many semiconductor manufacturers. For example ST Microelectronics uses the prefix HCF for the CMOS series ICs.

As long as the number '4017' is the same it should fit your needs.

To make the power LED flash use the timer circuit IC NE555 with different values for R1, R2 and C. The calculation formula is available in the data sheet.

Using 2K7, 680K and 1µF will make the LED flash at 1Hz.

Boncuk

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Proper Planning Prevents Piss Poor Performance

 

Hi! Thanks to Hero999, audioguru and Boncuk! I really appreciate your help.

Some of my questions were answered, thanks to you guys! But I still need to clarify certain points.

Okay.. So basically, here is what I understood.
1. Any replacement to ICs as long as same in part number will be okay for the circuit.
2. I should drop the voltage to 2V (typically, for LEDs) by using a resistor, and Ohm's law to compute.
3. I should definitely use crystal transducer instead of a piezo tweeter.
4. I must construct my own flashing LED.

Questions:
1. Q: What values should I use for trimmer resistors?

2. I don't understand a thing. Please do explain.

3. I must use crystal transducer. Is it commercially available?

4. The computation would drop the voltage. How about the current?

Plus:
I just want to confirm this thing about current. Which of the following is correct?
1. A power source delivers the amount of current 'full blast' to a component, so a resistor must be used to limit the amount.
2. A component uses only the amount of current it needs, regardless of the amount fed by the source.
If the answer is no.1, please do answer the next question:
How will I reduce the voltage AS WELL AS the current (that is, at the same time) by only using a resistor?


I know they're newbie questions, but I need technical answers. Please do help me. Thanks again in advance.

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-zeit-

 

No.
The resistor in series with an LED limits the current to 20mA so it doesn't burn out. The LED limits its own voltage.

I haven't seen a crystal transducer for about 45 years.
I don't think you will find an ultrasonic transducer that will survive the high power of this old project.

You can look at the original project or calculate the values for the amount of frequency change you want.

We talk in electronic terms. Please learn them.

A circuit uses only as much current as it needs.
An LED is a diode and will draw an extremely high current then will burn out if its current is not limited to an allowable current with a resistor in series with it.

A red LED is 1.8V to 2.0V and an old green LED is 2.2V. A new green LED, a blue LED and a white LED is about 3.5V. The current in an LED must be limited by a series resistor or current regulator circuit. They limit their own voltage.

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Uncle $crooge

 

an electronic Pest repellent? how about a cattle prod?

 

I don't know if rats and mice run away from cattle.
I don't know if rats and mice run away from an overloaded tweeter that can't produce ultrasonic frequencies.
Look what I found:

Attached Thumbnails

 

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Uncle $crooge

 

My dog hates the sound of a camera flash, she'll run when she hears it. Either that or she's camera shy.

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Bill
Smart Kits build Smart People
http://www.blueroomelectronics.com/

 

Hmm.. Thanks for the answers. I really do appreciate.

So you are telling me to drop this project. But we need a project that is useful at home. Can you recommend me some projects that are economically feasible to build? Please reply as I need to finish this project this sem. I will look into the forum but please advise me if you have anything to recommend. Thanks again audioguru!

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-zeit-

 

Make the old project but reduce the frequencies so that they are audible then use a normal speaker.
You can demonstrate how it produces switched frequencies and will repel humans.

Maybe you can set the frequencies into a little tune.

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Uncle $crooge

 

That's why hunters in Germany use ultrasonic pipes to call their dogs in the forest. The dogs can hear the pipe, the dear can't.

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Proper Planning Prevents Piss Poor Performance

 

Very interesting, but not proved.

We had an airfield equipped with 'Fouga Magister' jet trainers. They had very small turbines (size of a water bucket) running at 40,000rpm. There were no rats and mice in a radius of 15km around the airfield.

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Proper Planning Prevents Piss Poor Performance

 

@Boncuk

So you are telling me to pursue this project? Can you help me with the technicalities?
Thanks again!

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-zeit-