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What do you think of this circuit? Answered

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I made a few changes to a circuit, since it's the first time I do this I'd like to know what you think and if there's anything I should change.

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Josehf Murchison (author)2013-03-19

This is tested and works.
I modified your circuit so it would be controlled by Arduino.
First you connect the outputs of the Arduino to the 4 resistors feeding the transistors, then when you trigger 1 or more transistors to get these frequencies.

1 = 4800
1 + 5 + 9 = 4180
1 + 5 + 7 + 9 = 4110
1 + 5 = 3600
1 + 7 = 2880
5 + 7 + 9 = 2750
1 + 9 = 2400
5 + 7 = 2050
5 + 9 = 1800
7 + 9 = 1600
5 = 1300
7 = 960
9 = 755

The other combinations reproduce the same results.
You can increase or reduce the frequencies by changing the 0.1 capacitor up or down in value.
Is this what you wanted to do?

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user

That's great and yes it's what I wanted to do.
I'll try it, thanks!

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user

Can you read the schematic?

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user

Yes. I haven't worked with transistors yet but I have a few laying around, and I can understand the circuit.

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user

These are good sights to get datasheets on components.

http://www.maxim4u.com/

http://www.alldatasheet.com/

just enter the part number in the search box.

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user
Josehf Murchison (author)2013-03-02

what do you want it to do.

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user

I want to make an oscillator.

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user

I got that you want the oscillator to ????????????

You have three buttons and 8 possible oscillations.

What do you want the oscillations to do?

By the way where are you?

You should put your location in your profile.

It helps in that I have breadboards and over 100,000 components, I can test and tweak a circuit, then send the results to you (not everything someone might come up with) and you can order the parts on line and build it yourself.

After all we are here because we like to help.

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user

I want to connect an audio jack in the output and make an audio oscillator (sort of like the Atari Punk Console, just simpler).

I'm in a small city in Brazil, it isn't very easy to get components here, so please test it if you can.

Thank you.

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caitlinsdad (author)2013-02-28

What happens on the breadboard?

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pquadros (author)caitlinsdad2013-03-01

In theory it creates a square wave. Haven't tested it on breadboard because I can't get one locally.

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gmoon (author)2013-03-01

It's difficult to give advice when you haven't stated your goals.

However, a 102 cap is 1nF, not the 100nF in the original. So the output frequency will be significantly higher. Probably above the range of human hearing for two of your switches.

The POT closest to the 555 is the "octave" adjustment. It sets the tone "ceiling." Unless you're trying to chase off dogs, you might swap the 500K with the 5K in your drawing. With the current configuration, it will require 25K to 50K between pins 6 & 7 to produce an tone low enough to be audible (and that's somewhat dependent on the speaker). Otherwise, use a different capacitor to lower the overall frequency.

Again--we don't know your goals, so it's just speculation.

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pquadros (author)gmoon2013-03-01

I'm experimenting with oscillators. I changed the 100nF cap for 1nf since that's what I have, I want to make it using only what I have, but I might be able to scavenge a 100nF cap, so that isn't a problem.
The speaker I'm using is a regular computer speaker powered by USB, 8 ohm I think.

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